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Discussion Starter · #1 ·
I know this will be an easy question for some people here, what are the complete specs for the iron LT1 heads?

Combustion chamber cc?
Intake runner cc?
Exhaust runner cc?
Intake valve size?
Exhaust valve size?
Valve spring diameter and pressure?
Maximum valve lift?
Head gasket thickness?
Pressed or screw in rocker arm studs?

It would be nice to have this info stickied here in the engine section for quick reference. Even though I have plans for a 383, 396 build I want to freshen up my stock 350 by either rebuilding the iron heads or upgrading to some basic aluminum LE2 heads. If I do upgrade to the aluminum heads I want to make sure they have similar specs as the iron heads so that I end up with the same or better performance and the same CR as stock. If I reuse the iron heads, what is the part # for the Comp Beehive valve springs? I plan on using 1.6 ratio Comp roller rockers with the factory cam. Thanks for any help!

Steve
 

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Combustion chamber cc? 64cc
Intake runner cc? 170cc
Exhaust runner cc? 62cc (I think)
Intake valve size? 1.94"
Exhaust valve size? 1.50"
Valve spring diameter and pressure? 1.25", 75-80 seat
Maximum valve lift? .450" (varies head to head)
Head gasket thickness? .029"
Pressed or screw in rocker arm studs? pressed 3/8"
 

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I would think anyone into cars and engines that much would have a FSM.
 

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Have a lot of experience with the LT1 Iron Head.

The LT1 Iron Head has the Vortec Intake which is far superior to the Aluminum Heads.

Few inexpensive quick effective mods that wake up an Iron Head 350 LT1.

Clean up the Bowls with 80 Grit Flapper Paper, then 120 grit for Exhaust.
Clean and Polish Exhaust Port, 80 grit then 120 Grit Flapper.

Option, machine and add a high flow 1.60 Exhaust Valve.
Leave the Intake Port and Valve Size alone.

Plenty of Drop In Springs Selection.
Good Idea to Mil the Valve Guide Boss for the Damper Spring
or Use Beehives

Good for 20hp/30ftlb torque most above 2500rpm.
Doing most of the work yourself.
Parts and Machine Shop about $300.00.
Hope this helps.

d
 

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Discussion Starter · #12 ·
Is the only real difference between the 2 just the lack of cooling passages in the LT1 heads? I mean are all the specs like intake cc, combustion chamber cc and shape, exhaust cc, etc, the same?

Are there any well known iron LT1 head re builders that you guys would recommend? I do not trust most of the high volume engine/head re builders out there because they usually sacrifice quality for cheap parts and sloppy work.

Steve
 

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Is the only real difference between the 2 just the lack of cooling passages in the LT1 heads? I mean are all the specs like intake cc, combustion chamber cc and shape, exhaust cc, etc, the same?

Are there any well known iron LT1 head re builders that you guys would recommend? I do not trust most of the high volume engine/head re builders out there because they usually sacrifice quality for cheap parts and sloppy work.

Steve
I Port and Polish LT1 Heads.
My have been on the PINKS Car that Fred Diven and Chris own.
They can attest to the performance of the Heads..

D
 

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Is the only real difference between the 2 just the lack of cooling passages in the LT1 heads? I mean are all the specs like intake cc, combustion chamber cc and shape, exhaust cc, etc, the same?

Are there any well known iron LT1 head re builders that you guys would recommend? I do not trust most of the high volume engine/head re builders out there because they usually sacrifice quality for cheap parts and sloppy work.

Steve
DIFFERENT cooling passages. Yes, AFAIK all other specs the same.
For iron heads, I'd trust Dan. He's an IHRA/NHRA stock class racer, is meticulous and knows good parts from bad.
 

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Option, machine and add a high flow 1.60 Exhaust Valve.
Leave the Intake Port and Valve Size alone.

Plenty of Drop In Springs Selection.
Good Idea to Mil the Valve Guide Boss for the Damper Spring
d
Dan, don't forget to mill .020 thou off the deck to bring Comb chamber cc down and boost compression!

Nab
 

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Is the only real difference between the 2 just the lack of cooling passages in the LT1 heads? I mean are all the specs like intake cc, combustion chamber cc and shape, exhaust cc, etc, the same?

Are there any well known iron LT1 head re builders that you guys would recommend? I do not trust most of the high volume engine/head re builders out there because they usually sacrifice quality for cheap parts and sloppy work.

Steve
If I were going to have a set of iron LT1 heads (or any iron GM heads for that matter)worked/ported/whatever, I would contact Brzezinski to see what they could do. Impeccable work and quality from my experience, and they know their stuff on how to make power, and not just "flow numbers."

http://www.castheads.com/
 

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Dan, don't forget to mill .020 thou off the deck to bring Comb chamber cc down and boost compression!

Nab
That can be done however the Intake would have be milled and matched.
For a Race Engine yes .. agreed!
For a Street Engine.. not needed!

Want Power ... Zero Decking the Block.
More Compression Mil Heads 20 to 40 thou.
Use .015 Steel Gasket.
Suggest Chamfer and Smooth the Combustion Chamber.

With these Mods check Piston/Valve Clearance.

D
 
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