1969 z 302
 

I just acquired a 1969 Z28 car born with 302 DZ motor I have a question about cylinder heads has anybody ever heard of a 3947041 it's dated d17 of 9 the other head a 3927186 dated d25 of 9 and their factory DZ block is dated d18 of 9 the motor is all original do you think the head was replaced or would it come factory 202 with a 3947041 head everything else on the motor carburetor distributor alternator radiator trans rear everything's been untouched

Theoretically, it is possible. However, if it did turn out to be the original heads, I believe it would be the first known example of an 041 head on a Z/28.

I tore down a L48 in a 69 Impala that had one 186 head and one 041 head, and still had the factory steel shim gaskets with no sign that it had ever been apart. That was in the mid 90s. However, as you know, the L48 had 1.94 intakes.

I don't believe there has ever been a documented case of an 041 head with 2.02 valves from the factory. Quite a few have been modified for 2.02 intake valves. You might try a boroscope, but it would be really hard to tell if the head was machined for 2.02 intake valves from the factory without pulling it.

The date would make one believe it is likely original to the car. Hate to say never.

What is the assy date on the engine? Does it predate the D25 9 head? If so, most likely both heads were replaced at some time.

V0512dz

Dist 9D2, carb 943

Car car 05E

Alt 9C7,rad CH D ,rear 0515, trans P9E05

From what I have seen the 041 head was cast in Tonawanda and primarily used on the 300 Hp 350 applications to help supply the Flint plant due to high demand. It may be possible they could have machined a batch of 2.02 heads to replace the 186 heads in Hi Po applications. My 70 SS Camaro 350 was a 3970014 block cast in Tonawanda and used 041 heads.

I an aware that Camaro High Performance has seen 041 heads used on May built 302 engines. Also, a 350hp '69 Corvette.

Rare, but did happen.

I 50+ years being involved with machining/building SBC motors & a lot of 69 DZ302,s , I have personally never seen a 041 head that is a factory 2.02 x 1.60 . Not to say it didn’t/couldn’t happen but it would be interesting to see if that 041 head has machined/relieved combustion chambers around the intake valve as the factory production big valve head did. The factory relieved combustion chamber around the intake valve is hard to duplicate exactly even with today’s Serdi/Quickway type tooling.

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