Confused abut my heads!?

CoolvetteC3

New member
Joined
Dec 25, 2008
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4
Location
Sweden, EUROPE
Here´s the story:

I have this car since last year: www.coolvette.nu
The engine is a non matching number 350 cu, the cast number is 14016379 wich is supposed to be a late 1970´s 350 with 2 or 4 main bolt depending on wich source to rely on.

What makes me confused is the heads, the cast number is 462624 and that should (could) be small chambered and small valved heads according to this:
http://www.fastnuf.com/Headguide.html

On top of the same site there are the guide over cast marks where I can identify my heads as "G" witch goes straight against the cast number and indicates them to be a set of ´69-´70 300 hp heads...
:confused:

On the other hand, according to this: http://www.mortec.com/castnum.htm
these heads are 76 cc chambered with some different sized valves, at least by looking at the cast number.

What is the most important sign to look at to determine witch heads I actually have? Can the cast date help me to do this properly?
As far as I know this can be found under the valve covers, close to the cast number, is that correct?

What level of HP can I expect from this setup, the camshaft is unknown but the intake manifold is an Edelbrock with these numbers cast in: S.P.S-P. , an Edelbrock 1406, headers and Flowmaster silencers to create some great sound?
I expect it to deliver some more than the stock engines output of 190 HP but how much can the heads (whatever they are), the intake and the carb have added along with the headers and the freeflowing exhaust system?

Your guess is just an estimation I know, but I want to hear your guess nevertheless.

I complete this with a picture showing the engine stamp in front of the passenger side head:

Enginenumber.JPG


It seems incomplete, at least compared to the ones I have seen pictured on other sites.
Can anyone tell me what can be read from this?
 
Last edited:
Mortec seems to be the industry standard for this stuff. I'd go with them.
 
462624 is a 76cc open chamber smog head w/ 160cc intake runners, 1.5 & 1.96 valves. It's a lightweight casting, prone to cracking. Used on most late C3s, including 80 L48, L82, 81 L81 and 82L83, also on first 3 years of C4. These heads have long time after been sold as the GMPP performance iron head w/ screw in studs & guideplates, albeit with larger valves (1.6 & 2.02)

Basically, they are a POS head, poor for power. I have a couple of sets, I can't even give them away.

Realistic HP output? Honestly? Shy of 200 would be my guess.

The 462 closed chamber "fuelie" head is the 3767462, completely different head.
 
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