74 454 head gaskets ??
Thread Starter
Drifting
Joined: May 2005
Posts: 1,909
Likes: 6
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
74 454 head gaskets ??
I am amazed, but 3 North Atlanta Chevy dealers tell
me that they no longer carry any GM head gaskets
for a 74 LS4. (discontinued)
Does anyone know the correct thickness head gasket or have suggestions? Stock flat tops with a comp 268H cam.
Thanks.............
me that they no longer carry any GM head gaskets
for a 74 LS4. (discontinued)
Does anyone know the correct thickness head gasket or have suggestions? Stock flat tops with a comp 268H cam.
Thanks.............
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Call Summit or Jeg's. GM may have discontinued the gaskets which is really OK anyway. Fel-Pro probably made them for GM in the first place.
Just make sure to get the gaskets with the correct bore size. I've got Fel-Pro's on my BB, and I'm way over it. And 12.5 to 1 compression can be tough on gaskets with aluminum heads. So far, no problems..
Just make sure to get the gaskets with the correct bore size. I've got Fel-Pro's on my BB, and I'm way over it. And 12.5 to 1 compression can be tough on gaskets with aluminum heads. So far, no problems..
Pro
Joined: Nov 2004
Posts: 575
Likes: 0
From: Nice Lake Ontario
I believe GM used a stock steel shim gasket as original.
While the comp is rated at 8.25 or 8.5 in 74 it is actually in the 7.8-1 range
you might want to be sure you use a replacement shim gasket as a standard Fell-pro .040-45 thou gasket will lower your comp even more 
Mr Gasket makes a .020 thou shim gasket part #1131
While the comp is rated at 8.25 or 8.5 in 74 it is actually in the 7.8-1 range
you might want to be sure you use a replacement shim gasket as a standard Fell-pro .040-45 thou gasket will lower your comp even more Mr Gasket makes a .020 thou shim gasket part #1131
Thread Starter
Drifting
Joined: May 2005
Posts: 1,909
Likes: 6
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
I believe GM used a stock steel shim gasket as original.
While the comp is rated at 8.25 or 8.5 in 74 it is actually in the 7.8-1 range you might want to be sure you use a replacement shim gasket as a standard Fell-pro .040-45 thou gasket will lower your comp even more
Mr Gasket makes a .020 thou shim gasket part #1131
While the comp is rated at 8.25 or 8.5 in 74 it is actually in the 7.8-1 range
you might want to be sure you use a replacement shim gasket as a standard Fell-pro .040-45 thou gasket will lower your comp even more Mr Gasket makes a .020 thou shim gasket part #1131
I seriously do not know....better to ask now.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
If your cam lift is way over .500 then worry. Or if you're planning on 8000 + RPM.
As I recall a 454 has a 4.250 bore so 4.250 + .030 = 4.280 And they've got gaskets all the way to 4.600 probably in stock. I don't have a SUmmit catalog with me, and Jeg's doesn't list them all. Run down to Summit in Mcdonough..
If you end up with a shim type gasket, be sure and paint it with some Hi temp aluminum paint when you install it. The thicker ones go on dry.
As I recall a 454 has a 4.250 bore so 4.250 + .030 = 4.280 And they've got gaskets all the way to 4.600 probably in stock. I don't have a SUmmit catalog with me, and Jeg's doesn't list them all. Run down to Summit in Mcdonough..
If you end up with a shim type gasket, be sure and paint it with some Hi temp aluminum paint when you install it. The thicker ones go on dry.
Pro
Joined: Nov 2004
Posts: 575
Likes: 0
From: Nice Lake Ontario
That makes perfect sense...(.020).....But with the higher lift cam ... is there any chance that (even with flat tops) I might slam a valve into the top of a piston? I would hate to trash a new motor. The felpro OEM replacement that I bought today shows as .039.
I seriously do not know....better to ask now.
I seriously do not know....better to ask now.
I think you would have to have a pretty serious roller type cam to hit the flattops. I'm running .554 lift hydrolic on the exhaust & while I haven't quite got my motor together yet, from all the info I have gained from another site with some serious engine guys I am quite safe. In fact there's quite a few guys on that forum with exactly the same set-up working fine.
You could always set a head on with-out a gasket & measure your clearence? I don't think you'd touch the pistons even with-out a gasket on these 454s.
Then again...how MUCH cam you plannin on??
Thread Starter
Drifting
Joined: May 2005
Posts: 1,909
Likes: 6
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
Then again...how MUCH cam you plannin on??
Really not that much....Comp268H....Maybe the old steel shim WOULD give it the best compression. Hard to imagine that 10 - 20 thousands would make a difference, but the 74 BB didn't have much to begin with.
Thanks..........
Really not that much....Comp268H....Maybe the old steel shim WOULD give it the best compression. Hard to imagine that 10 - 20 thousands would make a difference, but the 74 BB didn't have much to begin with.
Thanks..........
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