1975 Heads question
Thread Starter
Drifting
Joined: Jun 2006
Posts: 1,327
Likes: 43
From: Vernon CT
1975 Heads question
Im looking to replace the heads on my L48 1975. I can buy some "Heads 64 cc Chambers These are the desirable 3947041X castings." I know absolutely nothing about heads. What are the considerations putting those on my 75? Or are there better choices? Thanks
Le Mans Master
Joined: Oct 2006
Posts: 6,842
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From: Palmdale CA
The L98 Aluminum heads off've the 4th Gen Corvettes have a 58cc combustion chamber and will bump up the compression by a good amount. Add an RV-4x4-Marine cam like the Lunati Voodoo cam with a lot of torque, a regular Edelbrock Performer and headers and you will have a lot of fun. I built an L48 like this for my '74. This combination, with a four speed, did low 14's at the drag strip. A good two seconds faster than stock.
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
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Cruise-In VIII Veteran
There are lots and lots of choices for your L48.
64cc combustion chamber size is fairly common amongst many brands.
Your choice will come down to budget and what other changes you are doing to this engine.
Basically, any aluminium head with 64 cc chambers will be an improvement over stock. Runner size is also important.
What are you building? Or simply replacing heads?
64cc combustion chamber size is fairly common amongst many brands.
Your choice will come down to budget and what other changes you are doing to this engine.
Basically, any aluminium head with 64 cc chambers will be an improvement over stock. Runner size is also important.
What are you building? Or simply replacing heads?
Le Mans Master
Joined: Mar 2004
Posts: 7,458
Likes: 1,484
From: Little Rock AR
The "041" heads are some of the best of the factory heads but any aftermarket head will work much better. They are equivalent to "double hump" castings but nobody wants these 041's because they just have no restoration use value. If the "041"'s were already rebuilt and very cheap you could run them. Usually, the cost to buy them, plus the cost to rebuild them will exceed the cost of a set of brand new aftermarket heads. The "041"'s in most cases just don't make any sense. They are limited to about 300 HP max in the common smaller valve versions.
Do you have a budget in mind for heads?
Do you have a budget in mind for heads?
Is my vette stock?? HAHA
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From: Im not allowed to tell you
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save your money adn go with an aluminum head...even a GM vortec head will be a better choice....whats your budget and when looking at Summit make sure you know you are buying individually or a pair
Tech Contributor
Joined: Aug 1999
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From: At my Bar drinking and wrenching in Lafayette Colorado
Lars
Thread Starter
Drifting
Joined: Jun 2006
Posts: 1,327
Likes: 43
From: Vernon CT
There are lots and lots of choices for your L48.
64cc combustion chamber size is fairly common amongst many brands.
Your choice will come down to budget and what other changes you are doing to this engine.
Basically, any aluminium head with 64 cc chambers will be an improvement over stock. Runner size is also important.
What are you building? Or simply replacing heads?
64cc combustion chamber size is fairly common amongst many brands.
Your choice will come down to budget and what other changes you are doing to this engine.
Basically, any aluminium head with 64 cc chambers will be an improvement over stock. Runner size is also important.
What are you building? Or simply replacing heads?
Thread Starter
Drifting
Joined: Jun 2006
Posts: 1,327
Likes: 43
From: Vernon CT
The "041" heads are some of the best of the factory heads but any aftermarket head will work much better. They are equivalent to "double hump" castings but nobody wants these 041's because they just have no restoration use value. If the "041"'s were already rebuilt and very cheap you could run them. Usually, the cost to buy them, plus the cost to rebuild them will exceed the cost of a set of brand new aftermarket heads. The "041"'s in most cases just don't make any sense. They are limited to about 300 HP max in the common smaller valve versions.
Do you have a budget in mind for heads?
Do you have a budget in mind for heads?
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Thread Starter
Drifting
Joined: Jun 2006
Posts: 1,327
Likes: 43
From: Vernon CT
Thread Starter
Drifting
Joined: Jun 2006
Posts: 1,327
Likes: 43
From: Vernon CT
Those are the standard 300-horse 1.94 intake iron heads for 1968-70. Nothing special about them at all unless you're doing a "numbers" restoration on a 68-70 with the right date codes. You'll wrap up more money rebuilding those heads than what you would pay for a nice set of well-flowing aftermarket aluminum heads. Total waste of time and money getting those heads - you'll raise your compression but do nothing for flow, so the performance increase would probably not be noticeable. I have flow tested the 3947041 versus the "X" heads, and there is no difference at all between the "X" and "non-X" heads - they flow as poorly as any other stock, iron 1969 head.
Lars
Lars