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Discussion Starter #1
I've been on this forum for a while. Seen so many different builds and swaps. For those of you that have modified your impala's engine and/or transmission, I would like some feedback as to what you would have done differently or do considering the advancements of newer engines and trannys.

I have my 95ss bone stock and would like to update the engine and maybe transmission. I have over 200k. No mods have been done as yet. What I'm looking for, is some more hp around 500. I do plan on adding a turbo depending on the motor
Appreciate the info.
 

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Hi, i think you have to have a plan/goal first. You talk about modifying the engine and tranny, and then you mention newer engines and trannies... You really need to pick a discussion as i think they are totally seperate AFA the answers you will get.

My vote is you already have a LT1 and 4L60E and this forum is full of recipes that work on how to build them and get the whole car working together for performance.

As many have said work from back of car forward.... exhaust, brakes, gears, tranny,engine, PCM tuning..

Good Luck and have fun.
P.S. over 300K on my DD keeps me busy enough just keeping it road worthy.
-ALF out....
 

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Questions:
1. Budget
2. Mechanical ability
3. Reliability - how important?


Given what I have in my engine and trans now, looking back, I'd have gone LS. That said, having a ballsy Gen2 in the age of "LS ALL THE THINGS" makes it an odd duck, which is also kinda cool.
 

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Depends on your HP/TQ goals. If below 450hp, LT1 is ok. Beyond that, LS. If you decide to stay LT1, there are cheap built LT1s for sale on the facebook group LT1 Nation all day long. Quality 4L60Es are generally readily available too but it's a lot harder to find build sheets for them than the engines. Going over 425hp in a 4L60E does make parts cost go up a bit but it's not horrendous.

Tuning is something to consider. Many more can tune LSs than LT1s. If you're willing to learn how to tune yourself, the 94-95 OBD1 LT1 setup is easy to tune via eehack. If that's not something you want to do and can't find an LT1 tuner nearby, LS might be a better way to go for you.
 

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Discussion Starter #5
Thanks for the info guys. I'm just trying to weigh the options of keeping stock engine or swap. Either way I want a Dailydriver out of it. Not planning on running on the track or racing.
From what I've seen builds with addons on the stock lt1 quickly add up to over 5k. So would it be better to build the lt1 or do a ls swap ?
 

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…..Either way I want a Dailydriver out of it. Not planning on running on the track or racing......So would it be better to build the lt1 or do a ls swap ?
Check my sig, bruh! And this is with a relatively mild cam.

But if you want 500hp to the wheels, reliability and be able to run it as a daily driver....then a heads/cam LS3 (or 6.2L LS) with about 11.3:1 static compression ratio is the way to go.

From personal experience.

KW
 

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Been on this forum for a while. Seen so many different builds and swaps. For those of you that have modified your impala's engine and/or transmission, I would like some feedback as to what you would have done differently or do considering the advancements of newer engines and trannys.

I have my 95ss bone stock and would like to update the engine and maybe transmission. I have over 200k. No mods have been done as yet. What I'm looking for, is some more hp around 500.
I do plan on adding a turbo depending on the motor.
Appreciate the info.
… I want a Dailydriver out of it. Not planning on running on the track or racing …
Sooner or later, you'll either sell the car, or rebuild the 4L60E.
Although a 4L60E rebuild that can withstand 500 horse & torque could cost over $2000, it's not a mod, it's maintenance, like tires or brake pads.

Unless you plan on racing, upgrading your rear gear from 3.08 to 3.42 gives more smiles per gallon, barely costs much if any MpGs, and you won't need a new driveshaft. ($800-$1000 installed)
With 3.73, you might or might not need a new driveshaft, and there's no cheap way to tell til after the deed is done. ($1300-$1500 installed)
Probably the most important performance mod, it makes every other performance mod more effective, and even helps the 4L60E last longer.

Mid-length or longtube headers ($1000-$1500) will extract the most from the 1.6 roller rocker upgrade ($500) for either your stock iron heads ($0), or your ported aluminium heads ($2500 installed).

(Ported heads {$2500 installed} with an OEM cam is senseless. If you're getting ported heads, get a cam {$3000 installed}.
It might not be so crazy to keep the OEM heads and upgrade the cam {$500 installed}.)

A RAISS or an SSRI3 ($250) is also tough to find, but you should be able to make a coroplast knockoff for about $100. Either way, install it yourself.

The 2nd most important performance mod is, without question, having your pcm reprogrammed, since it's also a maintenance upgrade.
For a nearly OEM car, there are some few options left for $200 or less - and frankly, there are still too many who have yet to do this to their bone stock LT1 cars, just plain DUMB.
For a car with all the aforementioned mods [especially cam and/or cam&heads], more like $250-$275.

If you still have money left to burn, upgrade the tires brakes steering and suspension BEFORE getting a bigger engine ($4000 or more).

How fast can you afford to go? …

(I'm not so sure our Iron LT1s like being turbocharged, something about the heads not holding boost too reliably well …)
 

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Even if you do not plan to tow anything, think of 3.42 or 3.73 as FIXING a very important thing, instead of 'changing' a major thing.
Superior rear gears help considerably to improve the longevity and durability of the 4L60E, our cars' major weakness.

More good news is that your city / metro / urban MpG will be improved by 3.42 or 3.73.

There are, however, a few potential drawbacks to 3.73 or numerically higher axle gears:
a. Highway MpG WILL suffer compared to lesser gears [in direct proportion to your highway cruising speed above 46MpH].

b. There is no surefire way to tell if your driveshaft will 'resonate' at ~63MpH or more, except to
either have your driveshaft balanced at unusually high speeds that are impossible for the vast majority of places,
or to install 3.73, and just HOPE your driveshaft doesn't try to impersonate a jumprope between 63 & 85MpH.
If it does, the only guaranteed cure is an even better driveshaft.
Having a 9C1 or WX3 driveshaft lowers the likelihood of resonance compared to civilian driveshafts, but by how much is, unfortunately, unpredictable.

c. If your exhaust upgrades and/or your roller rockers are noisy, your ears - or your significant other's - may wish you'd chosen 3.42.

d. Without 1.6 roller rockers AND reprogramming to raise the WOT upshift from 5100RpM to at least 6000RpM, no stopwatch has yet found a statistically meaningful difference between 3.42 & 3.73.

Some people could not possibly care less about any or all of the above. Others do [or worse, wish they had]. To find out which you are in advance, I present:

The 3.73 vs 3.42 Questionnaire
1. This is my toy, not my daily driver?
Y=3.73
N=3.42

2. I'm gonna race, or 'play hard' [for money]?
Y=3.73
N=3.42
(also see ?#6, unless you are kidding yourself)

3. I'm gonna tow/haul, or 'work hard' [for money]?
Y=3.73
N=3.42

4. I care more about city MpG, less about highway MpG?
Y=3.73
N=3.42

5. Many or mostly steep &/or long hills where I usually drive?
Y=3.73
N=3.42

6. I've an extra $600 lying around, just in case I NEED to buy and install a new driveshaft?
Y=3.73
N=3.42

7. My valvetrain has [AT LEAST] 1.6 roller rockers AND upgraded valvesprings to support a WOT UpShift of at least 6,000RpM [or higher]?
Y=3.73
N=3.42
(see ?#1)


If 'Y'=7, get 4.10 or more [especially when racing or towing is of the utmost importance]
If 'N'=4 or more, get 3.42 (3.23 or less are for 'non-enthusiasts')
If 'Y'=4 or more, get 3.73

Either way, some kind of kind of limited-slip differential is generally recommended by any and all, and would be foolishly ludicrous to omit.
 

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Boy it's sure gratifying to prove the old saying, "Evil minds thinks alike." Before any other replies I ended up with the exact same thoughts as about all the rest a ya's. Is the plan for about $8k doing everything yourself, or, twice that with a blank check to someone else.... You know, little details like that. And then, - the point? Is all that work ever going to the strip, or just the meanest beast on the interstate doing 45 on the way to work.... To laminate the dyno slip for the glove box? Out-pull (almost) everything domestic at lights for 1/3 the cost of a CTS-V?

So, 95- you answered most of those questions and the guys have great thoughts. With all due respect to this "500horse" thing, here's just a wild hare of a thought over Saturday coffee. You're starting with a bonestock quarter-century relic and classic in its own right. Guys, gals and even you will see its allure vanish every time you F with it. If compelled to the aforesaid, "F with it", then just a thought.

$3k in reversible bolt-ons to the motor, gives you plenty of power to achieve $2000 tickets plus maybe jail time in a big city.
$3k in suspension and brakes. The running gear under these 2-ton tubs is better than a lowly Caprice sure, but still decrepit compared to easy upgrades. 500horse ain't WAS if you can't corner over 25 anywhere.
$2k dolling up the paint.

With all that, if you're married, every male on the road will hate your guts. If single, all the gals will love you to death (ok at least your car).

See you blew lots of dough and have something awesomely satisfying. Instead of just another 500hp motor you can't do nothing with.


WOAH - I just spied that Marky has posted a treatice and have to go and read all that now. ;) More coffee.
 

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Discussion Starter #10
Marky Dissod. Excellent breakdown of options and cost on the stock motor. The gear ratio is an excellent tip. Thanks 👍
96 black I do plan on using the car to tow between 5-6000 lbs. That's one of the reasons I wanted the 500hp. But with all the bolt ons would do that without putting extra stress on the 4l60e. I'm leaning towards a 6.0 motor with possibly the 4l80e. I do plan on keeping the car another few decades 😏
I'll continue reading and following up on the best
Build options.
Thanks for the info 👍👍
 

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Marky Dissod. Excellent breakdown of options and cost on the stock motor. The gear ratio is an excellent tip. Thanks
96 black I do plan on using the car to tow between 5-6000 lb. That's one of the reasons I wanted the 500hp. But with all the bolt ons would do that without putting extra stress on the 4L60E. I'm leaning towards a 6.0 motor with possibly the 4L80E. I do plan on keeping the car another few decades
I'll continue reading and following up on the best build options.
Thanks for the info 👍👍
Ever heard of the Cadillac Fleetwood V4P?
From 1994-1996, The Cadillac Fleetwood V4P came standard with the Ironhead LT1 and a 4L60E, like most other B-cars including the Caprice / Roadmaster V92.
There are only two truly important differences between the Cadillac Fleetwood V4P and the V92s:
V4Ps came with 3.42 vs WX3/WX8's 3.08
V4Ps were rated to tow 7000lb with the shifter in OD, vs V92s rated to tow 5000lb with the shifter in D.

You don't need power for towing - it helps, of course, but it's not strictly needed.
As an example, the Chevy Silverado 1500 / GMC Sierra 1500 with the 4.3L LV3 V6 [rated @ 285 horse & 305 torques] is rated to tow 5500lb with 3.23, or 7000lb with 3.42.
To protect the 4L60E, rebuild it to withstand what you're gonna do to it, get it reprogrammed properly [with appropriate line pressures], and do the questionnaire again.

You don't need a 4L80E. It's not the 90s anymore.
Even GM powertrain will sell you a '4L70E' rated for 495 torques, or a '4L75' rated for 650 torques; both are based on the 4L60E.
You should have no problem finding a reputable rebuilder who can beef up your 4L60E to withstand an LS7 for less cost than GM's '4L70E'.
The money wasted transplanting a 4L80E, would be far better spent rebuilding the 4L60E to withstand a 6.2L or 6.5L Iron LT1, especially if you keep the 5.7L LT1.

Wish I knew more about which 383 or 396 LT1 engine builders had reputations for long lasting engines …
 

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Discussion Starter #12
So changing the gear ratios is the 1st thing I will do. Simple no major work. But now that you've mention, that I can just rebuild the 4l60e tranny to get more hp. Which is the best route to go. I see that sonnax have heavy kits that can go up to 900 hp but I'm sure that comes with a price and also made for racing not a DD. Other than sonnax, who else have good rebuild kits?
 

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I've been on this forum for a while. Seen so many different builds and swaps. For those of you that have modified your impala's engine and/or transmission, I would like some feedback as to what you would have done differently or do considering the advancements of newer engines and trannys.

I have my 95ss bone stock and would like to update the engine and maybe transmission. I have over 200k. No mods have been done as yet. What I'm looking for, is some more hp around 500. I do plan on adding a turbo depending on the motor
Appreciate the info.

I've been through a few different incarnations in my 96. Bolt ons, 396/LE heads and now the LSA setup I'm working on. I also had a procharged 383 caprice.

the current setup I'm working on is a LSX B15 crate engine topped with a ported LSA blower and backed by a Cahall Performance Ultra Pro Race 60e
What I would do differently? Probably not much. Shooting for 650-700whp and I think this setup will get me there just fine. I have a little worry in the back of my mind about the longevity of the trans, but I know guys like Impala Alex ran Cahall transmissions in much faster cars than mine and it lasted. I ran one in a 600whp procharged 383 caprice and had no issues with it either. the .70 OD of the 60e helps with drivability considering that many of the wide sizes for 17" wheels are fairly short tires (disregard that if you have larger wheels).


This is just my opinion from my experience with building various cars for both myself and professionally for a shop I used to work at, but my big kick these days is using a factory crate engine whenever possible to meet my power level goals. It isn't always the cheapest, but I just see so many benefits.

Example, say you are looking for 500RWHP. There are many ways you can skin that cat, but IMO, whenever your budget allows, you could achieve the power number with better drivability/reliability/gas mileage/longevity by letting the factory do your engineering for you. A crate LSA motor with just simple exhaust/intake/tune would make that power no problem; that's a stock factory motor designed to last 100K+ miles in vehicles daily driven in all conditions.

Not that there is anything wrong with building a motor, but if I had to put my money on which 500rwhp setup would have more problems down the road, worse drivability, a need for more maintenance etc... when comparing say a procharged 383 LT1 versus a stock LSA, my money is going on the built/aftermarket forced induction motor.

when I was thinking about what to do for my latest setup, I was torn between an LSA based setup or a gen V LT4. I knew I wanted a factory supercharged engine as I just loved the simplicity of those setups versus a turbo setup or procharger. Although there are some benefits to the LT platform, I think I made the right choice as for the time being the power differences between the two platforms doesn't seem to justify the added cost/complication of the swap. LS swaps are fairly straight forward in these cars, they've been done a thousand times by a thousand different people. There are formulas out there that are pretty easy to follow.


I can't really call it a regret, because I had a solid reason for not doing it, but I just wish I could have fit later model trans behind my setup like a 6L90e. They are known to work just fine behind huge power levels, more efficient gear spread, double OD. I just wasn't willing to cut the car up as much as I thought I'd have to in order to fit it.


Again, there are a lot of guys that won't agree with me on all of this. Some guys love building junkyard stuff and just doing stuff as cheap as possible not really caring about anything else but power numbers and cost, but the idea of dropping in factory power plants that make all the power you wanted without having to re-engineer them has really grown on me.

I have a 70 challenger with a 340 that I built. machined custom procharger brackets for, welded up custom piping, fuel injected, E85, solid cam etc and it's nothing but problems. Fingers crossed every time I beat on it. Valvetrain issues, always keeping one eye on the gauges. I built it from spare parts which was pretty cool, but I keep thinking I could score a used Hellcat engine and make the same power with a bone stock factory motor and a few bolt ons. When it comes to using an engine setup that you KNOW works and just having to go through the trouble of making it fit, versus taking something that fits already but modifying the hell out of it with aftermarket parts that may or may not stand the test of time, I take the former every time when building a car where longevity/reliability/drivability is of utmost importance.

For your weekend race car that you like to take out at night just to bring some friends out to eat at gapplebees, that's when I don't mind building stuff a little more radical.
 

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Discussion Starter #14
SSandman . I'm on board with ur suggestion of getting a factory engine but that upfront cost is a deterrent. Maybe if I can get it cheaper maybe from a salvage vehicle would be worth it.

"but I just wish I could have fit later model trans behind my setup like a 6L90e. They are known to work just fine behind huge power levels, more efficient gear spread, double OD. I just wasn't willing to cut the car up as much as I thought I'd have to in order to fit it."
Yes the 6l90e would be ideal if we could mount the LSA engine with it to get the full benefit. I think the 4l60e could be built to handle the power of the LSA.
 

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If you share a rough budget for your motor/tranny only, it will allow the smarter posters already here to drill down faster to your best options. All the other upgrades to support that are of course - additional. Note that as mentioned a stock tow Cady can pull as much or more as you want all day long, and at 6" more wb and 10% more weight than a b-body they've lured quite a few of us to the dark side for our DDs. [hashtag]$700-1,800 running, $4-6k for lo-milers.

Now I'll be first to admit sometimes not inclined to let a bunch of pertinent facts cloud up the issue, so if you're simply jonesing for an LS- swap then full steam ahead. ;)

Commendable you plan keeping it til it's 50+ years old. I do mine as well, and something makes me think, "100% orig. drivetrain" could become more attractive as these cars pass the 1/2-century mark then. To further this depravity of thought, my son's '88 Monte has got a nice 383, but I've got the 170k orig. motor squirreled away in the garage. lol
 

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Discussion Starter #16
96 Black. I not fully sure in the direction of ls swap or built motor heck this thread. Since the car is already 19 years old, I'm sure theres 1000s of threads of builds and mods although I'm not one to have gone that route. Experience is the best teacher so that's what I'm trying to see for the longevity of my car. I don't want to be building a monster to driver 85mph(waste of time and money).
"Commendable you plan keeping it til it's 50+ years old. I do mine as well, and something makes me think, "100% orig. drivetrain" could become more attractive as these cars pass the 1/2-century mark then". I agree with you 100%. If I go this route, I'd have to just redo the motor and tranny which will still cost about $3000 or more. So if I could get a better motor and built tranny for a few more $$ it would be better in my opinion to go the latter route.
 

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.....I do plan on using the car to tow between 5-6000 lbs. That's one of the reasons I wanted the 500hp.....
For towing, think more along the lines of torque, versus HP.

You can EASILY build a 500 hp motor and not have the torque to comfortably a two-ton trailer….let alone a three-ton trailer.

MAKE SURE....that you're focusing on the right thing.

KW
 

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Discussion Starter #18
Was speaking with a buddy of mines that's been building trannys for over 25 years. Suggested that the 4l60e can be built to any specs and still be a daily driver. I will definitely rebuild the 4l60e to match the hp of whatever motor I put it. So now onto the motor...sugestions?
 

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I have had a procharger on a relatively stock lt1, a supercharged stroker lt1, and now a high compression lt nitrous setup. After having all these setups I would do a lot different now. I would do a cam and head swap on the stock bottom end, 3500+ stall, and 4.10 gears. In my opinion, if you want to go much faster than that you need to do it on a platform that is not 25 years old and has more room to grow. (EDIT: LS swap)

Tuning these engines is not as simple as many lt enthusiasts lead people to believe. This alone is a major factor to consider. There are very few people who are still willing to tune these cars now. Imagine how it will be in another 5 years.
 

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I have had a procharger on a relatively stock lt1, a supercharged stroker lt1, and now a high compression lt nitrous setup. After having all these setups I would do a lot different now. I would do a cam and head swap on the stock bottom end, 3500+ stall, and 4.10 gears. In my opinion, if you want to go much faster than that you need to do it on a platform that is not 25 years old and has more room to grow.
OK, so, procharger, supercharger, high compression + chemical supercharging …

May I ask some questions?

1. Would I be correct if I guessed that you'd also be against turbocharging, for reasons related to your previous very-high-dynamic-compression experiences (plus turbos are more complicated)?

2. What gives you pause regarding a) boring, or b) stroking an Iron LT1? (Still dreaming of a 383 or a 395 by Ellwein …)
 
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