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Discussion Starter · #1 · (Edited)
Found this on another forum and didn't see a sticky here. So not sure if this data is on here any where if so then I can delete it, if not I think its helpful.

Intro:


It seems like several people every week want to know what cam is best for their LT1 powered car or what components they need to perform a cam swap. This guide focuses on the most common and proven camshafts available for LT1’s as well as the most common and proven valve train components. The majority of focus is on LT1 cars running stock bottom ends and stock heads however it still will offer some insight to those who have built bottom ends and head work. I encourage you to read the entire guide and hopefully you may learn something and allow yourself to select the perfect cam and valve train components for your particular setup.


Part 1: Choosing A Camshaft:


-Bigger is NOT always better.
-Sound does NOT equal power.
-Before selecting a cam you must develop your needs/wants/plans for your car, as that is what should determine which camshaft you select.




Ex: Stock 1996 B-Body Camshaft Specs: 191/196 0.418/0.430 lift 111 LSA


Duration: Duration is the time that the valve is open. Increasing the duration keeps the valves open longer which increases top-end power therefore raising the power band.
Lift: Lift is the maximum amount in inches that the valves are open. Increasing lift equals more horsepower and torque but at the same time can lead to more peaky torque curves.
Lobe Separation: Lobes Separation Angle (LSA) is the number of degrees the intake and exhaust lobes are separated. The lower the LSA is, the more overlap you have ,if the cam duration and lobe profiles remain the same.


OVERLAP:This is the killer for street engines. Overlap is the amount of degrees that the intake and exhaust valves are open at the same time. Unburned air/fuel mixture will be pushed through the cylinder when both valves are open and straight out the exhaust. This decreases mileage, increases emissions, and make the engine run rough at low rpms. It also decreases low-rpm torque, and hurts throttle response.
All cams have some amount of overlap. Stock cams all try to keep the overlap low for the above reasons.
More duration with no other changes will increase overlap. One way of lowering overlap after it's been increased by more duration is to increase lobe separation. This is because moving the lobes away from each other decreases the time they are open simultaneously.


-If you are in the market for a camshaft purely for sound and are willing to sacrifice usable power and drivability then something along the lines of the cc306 or GM847 will suite you well. However, if you want the full potential out of these cams you will need to be shifting at 6400+ rpm which is VERY risky on the stock bottom end. Some have been lucky while others have not but a stock block typically will not last long if being shifted at or above 6400/6500rpm. Just because camshafts as large as the cc306, GM847, etc. make more peak power, doesn't mean the car is faster. The key is usable power which is the power under the curve and you want a cam that fits in the usable power range that YOU want. Camshafts that large, lack low-end power because their power bands are more geared towards higher rpm's. Also, the worst thing you can do is run a cam of any sorts and not rev it to where it wants to be. Not revving a car out to where it wants to be will result in poor track times for your setup. An example below…

(Ex: I once ran the cc503 in my LT1 and shifted it at the stock shift point which is lower than desired for that particular cam. When I bumped the shifts up to where they wanted to be (6300ish) I picked up .4 and 4 mph in the quarter mile. If say I wasn’t willing to rev past 6000rpm, that cc503 would be hindering me. In that case I would be better off running a much smaller cam like the LPE 211/219 or something along those lines.)

***Now...I do not want you to think that the Comp 230/236, cc306, or GM847 etc. etc. are bad camshafts because they are not. Those cams have been proven for years to make great power and perform great at the track. Because of their large durations I like to use them as examples to prove points well. For some they may be the perfect camshaft choice but for most there tends to be better alternatives with a stock block/headed LT1, just depends what YOU want from the car. If you’re willing to rev the car out to where it’s deemed rather unsafe on the stock bottom end and your primary goal is to run the fastest ET’s possible then by all means they would be excellent choices. Unfortunately stock LT1 heads do not let these cams to be used to their full potential. Those with built bottom ends and head work greatly benefit from the use of these cams.***

-If you error on choosing a cam too small, you will still enjoy driving the car more than you did while it was stock and will be motivated to go a little bigger next time around. If you error on choosing a cam too large, it will more than likely hurt your enjoyment of driving the car compared to stock so the proper camshaft selection is very important.

-Below are some of the most popular and proven off the-shelf camshafts that will work great with LTx’s while performing well on the street and on the track. Also listed is the option to go the Custom Grind route. With today’s technology and the expertise and knowledge of certain individuals/companies, going with a custom grind is many times the best overall option.

***Keep in mind, the advertised rpm range of a particular cam given by the manufacturer is not necessarily 100% accurate and most cases it is not! Remember that the next time your looking through a catalog or on a website at a cam that you like.***


Custom Grind:

Pros: The optimal choice for the most power and best drivability because the camshaft is ground specifically for your setup and what you want out of the car.
Cons: Cost a little more than an off the-shelf camshaft (another $50-100 or so). If you change your setup down the road, the custom cam may not work to its potential on your new setup.
Pass Emissions?: Yes or No it’s up to you.
Shift Point for Maximum Performance: Wherever you are willing to rev it to.
Idle Characteristics: Whatever your looking for, from sleeper to choppy.
M6; Require Gears?: On a manual car, gearing plays a big part in cam size.
A4; Require Stall?: On an auto car, more stall is needed for larger cams but a custom camshaft can be designed around your existing or planned stall size.
Where can I get a Custom Grind?: A few places offer custom grinds with the most popular in the LTx crowd being Lloyd Elliott and Advanced Induction. Other good choices are Ed Curtis and Cam Motions.


Comp Cams:


cc502: (218/224 .528/.537 112lsa) w/ 1.6RR's
Features Comp's relatively newer technology XE (Xtreme Energy) lobes for more top-end power. Exhibits great drivability with a strong mid-range and moderately good top-end. Similar to the LT4 “Hot Cam” in performance and drivability.
Pass Emissions?: Yes
Shift Point for Maximum Performance: 6100-6200rpm
Idle Characteristics: Moderately Choppy Idle
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed


XFI 466: (218/224 .570/.565 113lsa) w/ 1.6RR's
A newer grind from Comp Cams. It utilizes their very aggressive XFI (Xtreme Fuel Injection) lobes that are good for increased power over older technology lobes like Magnum etc. Along with excellent drivability it exhibits a very strong mid-range with a good low-end and moderately strong top-end. Essentially a beefed up LT4 “Hot Cam” and cc502. With its 113lsa it takes a more trained ear to know that it’s there making it a decent “sleeper” cam. Note: Due to its very aggressive lobe design, requires the use of “Beehive” valve springs.
Pass Emissions?: Yes
Shift Point for Maximum Performance: 6100-6200rpm
Idle Characteristics: Smooth Idle
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed


cc305: (220/230 .544/.544 114lsa) w/ 1.6RR's
Features Comp’s Magnum lobes with are older technology but proven not to take a beating on valve train components. Comes in a 112lsa and 114lsa. The 112lsa will have slightly more top-end power over the 114lsa which will have slightly more low-end power. The 114lsa is sometimes favored by cars running Nitrous or Blowers because it provides less overlap than the 112lsa. The less overlap leads to more potential power from the Nitrous/Blower. In the case of Nitrous your typical 75-150 shot will not really benefit from the 114lsa over the 112lsa, different when the shot increases beyond that however. Pretty comparable to the LT4 “Hot Cam” in terms of power with the cc503/GM846 a step ahead.
Pass Emissions?: Yes
Shift Point for Maximum Performance: 6200-6300rpm
Idle Characteristics: 114lsa will have a Smooth Idle, 112lsa will have a more Choppy Idle
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed
 

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Discussion Starter · #2 · (Edited)
cont.

cc503: (224/230 .537/.544 112lsa) w/ 1.6RR's
Widely known for being the biggest cam you want to run on a stock headed car without sacrificing usable power and drivability. Features Comp’s relatively newer XE (Xtreme Energy) lobes for increased top-end power. Has a very strong mid-range with strong top-end power without much if any loss in the low-end. Similar to the GM846 and good for a solid 10-15hp/tq throughout over the “Hot Cam”, cc305 etc. May have some cam surge, depends how good the tune is.
Pass Emissions?: No, requires tuning to pass
Shift Point for Maximum Performance: 6200-6400rpm
Idle Characteristics: Choppy Idle
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed


XE 230/236: (230/236 .544/.555 112lsa) w/ 1.6RR's
Features Comp’s relatively newer XE (Xtreme Energy) lobes for increased top-end power. An excellent selection for the individual stuck between the cc503 and the cc306 or the GM846 and GM847 etc. Because of its more aggressive lobe design it will perform similar to its larger cc306 cousin while exhibiting slightly better drivability. Expect a very strong mid-range and top-end with some loss in the low-end. The beginning of pushing it with a stock bottom end and more recommend for cars that aren’t daily drivers. Works very well in cars with built bottom ends and head work. Automatics require high-stall converters and gears and 6-speeds require steep gearing to run this cam successfully. May have some cam surge, depends how good the tune is as well as stall size/gearing.
Pass Emissions?: No
Shift Point for Maximum Performance: 6400+rpm
Idle Characteristics: Choppy Idle
M6; Require Gears?: Yes
A4; Require Stall?: 2800+ Stall Speed


cc306: (230/244 .544/.576 112lsa) w/ 1.6RR's
Features Comp’s Magnum lobes with are older technology but proven not to take a beating on valve train components. Has been proven over the years to make good numbers and perform well at the track. Similar in power output with the newer XE 230/236 with slightly worse drivability. Exhibits a very strong mid-range and top-end with some low-end loss. Not recommended for cars that are daily drivers or that have stock bottom ends/heads due to its large size in duration. Stock heads don’t allow this cam to be used to its full potential so one with a built bottom end and head work would benefit greatly from this cam. Automatics require high-stall converters and gears and 6-speeds require steep gearing to run this cam successfully. Degree of cam surge will be determined by how good the tune is, stall size/gearing etc.
Pass Emissions?: No
Shift Point for Maximum Performance: 6400+rpm
Idle Characteristics: Very Choppy Idle
M6; Require Gears?: Yes
A4; Require Stall?: 2800+ Stall Speed


Crane Cams:


Crane 227: (210/224 .511/.553 112lsa) w/1.6RR's
Good proven performer on stock heads. Stock LT1 heads have restrictive exhaust ports relative to the intake ports and the 227's wide split in duration helps balance that out. The 227's low-end power starts low and is consistent through the entire mid-range making it a popular choice among guys with heavy B-Bodies. Will have stock like drivability and is known to be a torque monster. Lope is not very noticeable making it a nice “sleeper” cam.
Pass Emissions?: Yes
Shift Point for Maximum Performance: 6000-6200rpm
Idle Characteristics: Smooth Idle with a Slight Lope
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed


GMPP:


LT4 “Hot Cam”: (218/228 .525/.525 112lsa) w/ 1.6RR's
An older technology design that has proven itself in reliability and decent power output. Exhibits great drivability with a nice mid-range, step up from the factory LT4 camshaft hence the "Hot" in LT4 "Hot Cam". A good selection for the person who doesn’t want to do research or have the best cam out there due to the ease of purchasing the entire kit. Similar to the cc502 and cc305 with the XFI 466 having a decent edge on it and the GM846/cc503 putting out another 10-15hp/tq throughout with similar drivability.
Pass Emissions?: Yes
Shift Point for Maximum Performance: 6100-6300rpm
Idle Characteristics: Slightly Choppy Idle
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed


GM846: (222/230 .543/.563 112lsa) w/ 1.6RR's
Right there with the cc503 in terms of being widely known for the largest cam you want to run on stock heads and retain good drivability and usable power. Has a very strong mid-range and good top-end power without much if any loss in the low-end. Similar to the cc503 and good for a solid 10-15hp/tq throughout over the “Hot Cam”, cc305 etc. May have some cam surge, depends how good the tune is.
Pass Emissions?: No, requires tuning to pass
Shift Point for Maximum Performance: 6200-6400rpm
Idle Characteristics: Choppy Idle
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed


GM847: (234/242 .575/.595 112lsa) w/ 1.6RR's
The largest cam of the bunch. Over the years it has proven itself as a cam that puts out good numbers and good track times. Very strong mid-range and top-end with some low-end loss. Will put out slightly better numbers than the cc306 while exhibiting similar drivability. Not recommended for cars that are daily drivers or that have stock bottom ends/heads due to its large size in duration. Stock heads don’t allow this cam to be used to its full potential so one with a built bottom end and head work would benefit greatly from this cam. Automatics require high-stall converters and gears and 6-speeds require steep gearing to run this cam successfully. Degree of cam surge will be determined by how good the tune is, stall size/gearing etc.
Pass Emissions?: No
Shift Point for Maximum Performance: 6400+rpm
Idle Characteristics: Very Choppy Idle
M6; Require Gears?: Yes
A4; Require Stall?: 2800+ Stall Speed


Lingenfelter Performance Engineering:


LPE 211/219: (211/219 .530/.560 112lsa) w/ 1.6RR's
Has stock-like drivability and known to have instant torque in the low rpm's. Very comparable to the Crane 227 with its low rpm power that comes in early and is consistent throughout the mid-range. Lope is not very noticeable making it a nice “sleeper” cam.
Pass Emissions?: Yes
Shift Point for Maximum Performance: 6000-6100rpm
Idle Characteristics: Smooth Idle
M6; Require Gears?: No
A4; Require Stall?: 2600+ Stall Speed


Other:


**Some camshafts that have better alternatives:**

Edelbrock 218/218 .525/.525 112lsa: Not too many people have ran this particular cam but for those that have the results have been less than stellar. Some good alternatives that are similar in size would be the cc502 or XFI 466.

LPE 219/219: This is a great cam but it was developed more for the L98 motors. A great alternative would be the LPE 211/219.

**There are some more camshafts available for the LTx motors however the ones listed are some of the more common and proven choices. This is just to get you on the right track so remember you are not limited to what is above but they are all good choices that most would recommend.**
 

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Discussion Starter · #3 ·
Part 2: The Components Needed For A Cam Swap


The following are the recommended/required components needed for doing a cam swap. The valve train is not a good place to cut corners with. In terms of doing the valve train it is recommended to do it right the first time, so it can all be done one time and one time only.


A. Valve Springs:

Purpose: Keep the valve in control.
Benefit of Upgrading: Upgrading the valve springs is ABSOLUTELY mandatory in doing a cam swap. The stock valve springs CANNOT handle any more lift or RPM than the stock cam puts out as well as a cam with a more aggressive lobe design.
Required: YES.
Popular Choices: Crane Dual Spring Kit 10308-1 (includes locks, retainers, shims), PAC Beehives 1218 or Comp Cams Beehives 26918.
Note: Make sure the valve springs you purchase are matched to the camshaft you plan to run. You do not want the valve springs to go into coil bind which is maximum compression of the spring till its solid because this will cause a major failure in the motor.
Along with valve springs, you will need locks, retainers, shims, and valve stem seals (16). The LT4 valve springs located in the LT4 "Hot Cam" kit should NOT be considered to be run with any cam due to the fact they are known to be very weak and only have a max lift rating of .540 which is not high enough for most off the-shelf camshafts.

B. Roller Rockers:

Purpose: Transfers the motion of the cam along the pushrods and assists the valves to open.
Benefit of Upgrading: Upgrading from the stock 1.5 stamped steel rockers to 1.6RR's will increase the lift that the camshaft is putting out as well as producing an extra degree or two of duration at the valve and increased overlap.
Ex: Lift of cc503 w/1.5 RR's = (.503/.510) divide by 1.5 then multiply that number by 1.6 to get lift with 1.6RR's = (.537/.544).
Required?: No, but highly recommended.
Popular Choices: Crane Golds, Comp Cams Magnums, Comp Cams Pro-Magnums.
SA or NSA?: Self-Aligning should work fine for some of the smaller camshafts that do not see revs past 6200/6300rpm. Non-Self Aligning is cheap insurance that can handle high rpm rev's better because the use of guide plates will ensure that the rockers cannot slip off the valve tips. NSA use 7/16" studs which is stronger than the 3/8" studs that most SA rockers have. Non-Self Aligning will require the use of hardened chromemoly pushrods, studs, and guideplates (8).

C. Pushrods:

Purpose: Transfers the motion of the cam to the roller rockers.
Benefit of Upgrading: A stiffer pushrod helps to reduce pushrod flex and along with the valve springs helps to keep the valves under proper control and away from valve float. Upgrading the pushrods is important for durability of the system and should be done when upgrading the cam.
Required?: No, but highly recommended.
Popular Choices: Chromemoly 5/16" or 3/8" outside diameter. Hardened chromemoly pushrods are required if using guide plates. The Trick Flow’s tend to be the most popular and proven choice.
Note: Pushrod length should be checked on any camshaft or change in the cylinder heads. There are a lot of variables that can change the length of the pushrods needed from camshaft base circle, deck height of the block, milling the heads, valve job height and valve length. If the pushrods are too long or too short they will cause premature wearing of the guides and valve train failure could be possible. LT1's with stock heads (assuming none of the mentioned changes have been done) will more than likely still use stock length 7.200" pushrods. It is so easy to measure pushrod length that it should be done regardless. A very easy to use tool to measure pushrod length is the Comp Cams pushrod length checker part# (7702-1).

D. Lifters:

Purpose: Rides along the lobes as the cam rotates around and follows cam up the lobe ramp which pushes the pushrods up.
Benefit of Upgrading: Over time with higher mileage motors the lifters tend to wear out.
Required?: No, highly recommended for higher mileage motors.
Popular Choices: GM LS7 lifters, Comp Cams hydraulic roller, Crane Cams hydraulic roller.
Note: Yes the LS7 lifters will work in an LTx motor, they are one of the only interchangeable components between LSx and LTx motors. If you go to your local GM dealer to order lifters for your LT1, they will give you LS7's because they are the newly revised replacements.

E. Others:

Gaskets: The following gaskets will be needed:
Front timing cover gasket, optispark seal, crank seal, water pump drive seal, egr gaskets, throttle body gasket, intake manifold gaskets, valve cover gaskets, water pump gaskets.

Timing Chain: Over time the stock timing chain wears and can develop slack. It is highly recommended to swap out the chain for a new one. A stock LT1 replacement chain from GM will do just fine for most.
Note: An LT4 timing chain will NOT fit on LT1 sprockets.

Valve Stem Seals: Worn out valve stem seals will allow oil to come up through the valves which leads to accelerated oil consumption and blue smoke coming from the exhaust. The perfect time to replace them is during a cam swap and for the low cost of them it should be done every time without doubt.

Optispark: If the optispark has not yet been changed it is a good idea doing so at this point. Whether you're doing the cam swap yourself or having it done by a shop, the optispark distributor has to come off. Therefore, it is the easiest time to replace it and will save you time and effort in the long run. If your having a shop do the swap it will not cost you any extra money to have it installed considering the old one comes off and gets re-installed again which will save you money of having it done again down the road.

Water Pump: Same goes for the water pump as with the optispark. If the mileage is getting up there or the pump is starting to show signs of leaking this is the time to replace it. It will save you time, effort, and money to do it at this time.


Conclusion:

Your typical cam swap will run roughly $1,000 in parts alone. That’s not including if you replace the Optispark or Waterpump etc. Labor depends on the shop and part of the country you live in but figure $600+. Tackling a cam swap yourself can easily be done with the right tools and patience. It is smart to start with bolt-ons before at all considering a cam swap. Without the proper intake and exhaust modifications a cam will be choked hindering performance greatly. If the car is auto it is highly recommended to put a stall converter in the car before a cam. Drivability will be poor and performance marginal without the use of a proper sized stall matched to the cam. Lastly, a tune should be on order after any cam swap. Poor drivability and performance will be the result of leaving the stock tune in while running a cam. I hope this guide proved useful to you and good luck with your cam swap!
 

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Found this on another forum...

Ex: Stock 1996 B-Body Camshaft Specs: 191/196 0.418/0.430 lift 111 LSA

Lobe Separation: Lobes Separation Angle (LSA) is the number of degrees the intake and exhaust lobes are separated. The lower the LSA is, the more overlap you have.
Anyone besides me have a problem with the hi-lited statement above?
Anyone know what the LSA/LCA for the OEM F-body cam is along with its OL? How 'bout the OL of the OEM B-body cam?
 

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Discussion Starter · #5 ·
Anyone know what the LSA/LCA for the OEM F-body cam is along with its OL?
Stock 1997 F-Body Camshaft Specs: (200/207 .447/.459 117 LSA)
 

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Stock 1997 F-Body Camshaft Specs: (200/207 .447/.459 117 LSA)
"Anyone know what the LSA/LCA for the OEM F-body cam is along with its OL? How 'bout the OL of the OEM B-body cam?"

I can supply the OL figures (and the open/close points which makes figuring out the OL possible) for both if you are unable to find them. Bear with me Eric, as the OL figures are important and relevant to my question. I just figured it would mean more if you posted them. With the LSA/LCA for the two cams being dramatically different, it makes the OL comparo that much more important and my question more compelling.
 

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Discussion Starter · #7 ·
I can supply the OL figures (and the open/close points which makes figuring out the OL possible) for both if you are unable to find them. Bear with me Eric, as the OL figures are important and relevant to my question. I just figured it would mean more if you posted them. With the LSA/LCA for the two cams being dramatically different, it makes the OL comparo that much more important and my question more compelling.
What do you mean by OL?
 

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What do you mean by OL?
OverLap, the amount in degrees when both valves are open, or in the case of the OEM cam spces, a lack of overlap, necessary for emissions compliance. The amount in degrees measured in the area of TDC after the intake opens and before the exhaust closes. I state lack thereof as the OEM specs will be negative (lack of overlap) thus measured when from the time the exhaust closes and before the intake opens.
 

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The original poster should change the sentence to "The lower the LSA is, the more overlap you have, if the cam duration and lobe profiles remain the same."

F-body/Y-body cams have the same overlap as the b-body cam by having higher duration and LSA.

Poor driveability is caused by a combination of too much duration and overlap. The former is usually the problem.
 

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Discussion Starter · #10 ·
I state lack thereof as the OEM specs will be negative (lack of overlap) thus measured when from the time the exhaust closes and before the intake opens.
I found that the cam on the LT1 for the Corvette has 41 degrees. Sited here:
http://www.grandsportregistry.com/lt1vslt4.htm

Also found this:

OVERLAP:

This is the killer for street engines. Overlap is the amount of degrees that the intake and exhaust valves are open at the same time. Unburned air/fuel mixture will be pushed through the cylinder when both valves are open and straight out the exhaust. This decreases mileage, increases emissions, and make the engine run rough at low rpms. It also decreases low-rpm torque, and hurts throttle response.
All cams have some amount of overlap. Stock cams all try to keep the overlap low for the above reasons.
More duration with no other changes will increase overlap. One way of lowering overlap after it's been increased by more duration is to increase lobe separation. This is because moving the lobes away from each other decreases the time they are open simultaneously.


The original poster should change the sentence to "The lower the LSA is, the more overlap you have, if the cam duration and lobe profiles remain the same."

F-body/Y-body cams have the same overlap as the b-body cam by having higher duration and LSA.

Poor driveability is caused by a combination of too much duration and overlap. The former is usually the problem.

Noted.
 

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I found that the cam on the LT1 for the Corvette has 41 degrees. Sited here:
http://www.grandsportregistry.com/lt1vslt4.htm
I have NO idea what that 41º is for or what it pertains to.

This is fast becoming apparent where something is referenced (still haven't noted what forum you obtained it from) and the OP has no idea what has been posted, and without a high enough level of backround knowledge is unable to determine whether the info is factual
or not.
Also found this:

OVERLAP:
This is the killer for street engines. Overlap is the amount of degrees that the intake and exhaust valves are open at the same time..... This decreases mileage, increases emissions... All cams have some amount of overlap. Stock cams all try to keep the overlap low for the above reasons.
More duration with no other changes will increase overlap.
That statement is misleading in that it does not identify at what lift the duration is measured from. Granted OEM cam lobes have been known to have very mild/gentle acceleration ramps and in the past (I say past as the duration from zero/.001" for these LT1/4 cams is not noted) very aggressive solid lifter SBC cams have had as much as 360º of duration measured from virtually zero/.001" lift. The reason for the present day practice of measuring lift @.050" is that it gives a more accurate indication of the effective duration from a lift where measurable airflow is actually recordable. The question then is at what lift off the seat is measureable flow established.

ALL have some OL? Measured from what lift figure? Reread my above post. There is a diff between positive and negative OL. Again, measureable with an indiator but is it measureable with a flowbench and thus able to establish meaningful airflow? So claims the linked site, but I'd rather obtain the actual lift points at which the OL is zero and determine for myself whether there is any meaningul OL overall. If the EGR hardware could be eliminated with the LT4 cam with a decrease of the negative (measured @.050") OL by ~6º apparently it affected flow enough that it had at least some effect on EGR.

Eric, as it appears you are having a problem understanding OL as well as difficulty in providing OEM specs for same for both the B and F engines, I'll note them here.

Even though the LSA/LCA is much different between the two, the amount of (neg.) OL is -28.5º for the B and -29.5º for the F.

Noting that along with the LCA/LSA for both should be revealing. For reasons including the fact that the same LSA figure can be generated many different ways with cams of greatly differing operating characteristics, for all but the diehard detractors in denial, it should be apparent that LSA/LCA means virtually NOTHING. An engine pro (a real pro and not a resident forum member, BTW) whose claim to fame was building Winston Cup engines has stated that you can take all the info you've learned regarding LCA, gather it together and throw it in the trash. LCA means nothing. Apparently, I am alone (on this forum) that understands that. I'll take it one step further...
I have yet to find ANY pro tuner, ANY (true) pro engine builder, or ANY (true) cam designer (not pseudo designers such as BB or LE, though I think LE is a class act) that will disagree with my above LSA/LCA position. NOT ONE!!! Now others will be aware of the degree of separation (yes, a big pun intended) there is between what the membership of this forum accepts and believes, and what the true pros/myself actually know.

Frankly, I use that as a 'litmus' test of sorts. If someone claiming to know cams starts using the buzzword/initalism LSA from a positive perspective, is actually just attempting to impress others with how very little he knows about cam features and their characteristics.

EDIT:
Why today's more popular cam suppliers have chosen to dumb down the average enthusiast with BS rather than educate them with sound information as the cam pioneers of the 50s-60s chose to do, I have NO idea.

The sooner one removes the initialism LSA from his vocabulary the sooner the barrier will be removed to truly understanding the science of the cam. Obviously, no one on this fourm agrees with me as I've attempting to educate numerous times (archives?) in the past... not unlike attempts with the manifold comparo.
 

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Discussion Starter · #12 ·
Yes I'm still learning. Thanks for the info.
 

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I would agree. It's a popular thing since it is "mainstream" even though its not a correct measure of a cams "worth". I could see it however being used to describe a certain "functionality" of a cam. Those of us that understand cams even reasonably well would further to guess that when someone says I have a 103 LSA cam in my 350 ci engine, to me that means a peaky high revving power curve, Highly dependent on a high numeric gear and radical stall, vs a 117 LSA cam in the same engine to me intones a softer broader power curve. Even intones a certain laziness i the engine if you will. I agree, that the sooner we move past the LsA describing a cams operational characteristics the better. In fact the term really was never meant to be circulated like it has been.

I have NO idea what that 41º is for or what it pertains to.

...(deleted stuff)...
Why today's more popular cam suppliers have chosen to dumb down the average enthusiast with BS rather than educate them with sound information as the cam pioneers of the 50s-60s chose to do, I have NO idea.

The sooner one removes the initial-ism LSA from his vocabulary the sooner the barrier will be removed to truly understanding the science of the cam. Obviousl, no one on this forum agrees with me as I've attempting to educate numerous times (archives?) in the past... not unlike attempts with the manifold comparo.

One of the most helpful replies from you yet. Spot ON! Keep working at it.(NOT condescending attitude from me)

Your pal,

Chris
 

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I believe that the op got this info from the ls1lt1.com forum. I have seen it before a few times and im almost certain that's where i saw it.
 

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Discussion Starter · #15 ·
I believe that the op got this info from the ls1lt1.com forum. I have seen it before a few times and im almost certain that's where i saw it.
Close. Its been around a few forums and I thought it was good info to post here for people who dont know what to look for in a camshaft.

http://www.ls1tech.com/forums/lt1-l...lt1-camshaft-valve-train-selection-guide.html

I don't mind the ribbing (no ****.) There is a lot to learn and I am no means an automotive mechanical engineer.
 

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Wow! More inaccurate wording or misinformation from a respected? site!
ALL do NOT have some OL. Reread my above post. There is a diff between positive and negative OL.
It really depends on what lift you are measuring the overlap at. Mathematically speaking, overlap can be estimated by adding IVO timing event to the EVC timing event at a specific valve lift.

What this means is overlap at the advertised duration lift will be significantly higher than overlap at .050" lift. And it will be positive even for stock emission cams.
 

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A challenge!

As brought to light by the post of RA383, I believe I was unnecessarily critical of the OL wording on the LT1/4 comparo site linked earlier. I want to note that I edited my post as to be less harsh toward that site, though to bring attention to the edit is not the reason for this post. It is a challenge of sorts. Allow me explain.

The main purpose of this post has to do with the edited wording of my post that includes the following.
ALL have some OL? Measured from what lift figure? Reread my above post. There is a diff between positive and negative OL. Again, measureable with an indicator but is it measureable with a flowbench and thus able to establish meaningful airflow? So claims the linked site, but I'd rather obtain the actual lift points at which the OL is zero and determine for myself whether there is any meaningful OL overall. If the EGR hardware could be eliminated with the LT4 cam with a decrease of the negative (measured @.050") OL by ~6º apparently it affected flow enough that it had at least some effect on EGR.”

In the past while turning the degree wheel I had not ever had the need or even the thought of determining the duration @ .xxx" lift to generate a zero OL figure. IOW, degreeing or at least establishing a base for the cam to allow experimenting with different lift starting points until a zero OL figure was achieved. As I do not have the time at the present to undertake such a project I thought someone else would be interested in finding out this info. I also do not have an LT4 cam available to use, however an OEM F or B body cam could be used for this experiment as I have no reason to believe their ramps would be any different than the LT4 ramps, so the data collected should be valid. Anyone interested? There must be others beside myself that know how and actually have experience degreeing cams that one could be found among that group willing to take the time. How ‘bout one the cam experts here that have been so ardent in their disagreement with my position on LSA/LCA? Among those experts there must be at leat a few with cam degreeing experience. How else could they be experts, right? Any of those willing to take on the project? Regardless, it doesn’t matter who takes it on as long as someone with degreeing experience would follow through.

What data would actually be determined? By establishing at what lift the F and/or B cam would generate zero OL we could determine the lift that would be necessary to have an effect on the EGR to the degree (no pun intended) of negating the need for the EGR hardware with the use of the LT4 cam. As noted in my edited post above, the LT4 cam has ~6º of additional OL @.050” lift. So we have whatever data we need to learn the effective OL at a designed lift to have an effect on EGR. I don’t know ‘bout you but I would consider that worthwhile info to know. I also believe it would also provide this site with info no other auto site has or has attempted to gather. :)
 

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Discussion Starter · #19 ·

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Nice

BY FAR THE MOST COMPREHENSIVE, WELL WRITTEN, AND HELPFUL thing I've ever read on Cams, thanks for the post!!!!!
 
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