427CI - 435HP Block

[Ray C.]

I have very little knowledge about big blocks Corvettes. At a car cruise last evening a person stated that original big blocks would have "HIGH PER" cast in the rear of the block for Corvette blocks. What are the identifying indicators for a correct Corvette 427CI block ?

Thanks for any information!

Ray

[Joel Falk]

Re: 427CI - 435HP Block

Mainly the casting number, pad stamping, and four bolt mains. I do not think the "Hi Perf" designates anything reliably, and the casting number can have other uses as well.

For example, in 1967 the 3904351 block was used in Impalas and Corvettes. The low HP cars had 2 bolt mains and the 435's had 4 bolt. Very early and late cars might have had a different casting.

[Ray C.]

Re: 427CI - 435HP Block

Thanks! Joel

I may have phrased the question wrong. I should have stated; were there any 427 blocks cast with the words of "HIGH PERf". A friend has a 427CI 435HP and became very concerned when this topic came up last evening.

Thanks for any information!

Ray

[Don 42616]

Re: 427CI - 435HP Block

Yes, The Hi Pref is cast on BB.

[Mark #28455]

even 2 bolt blocks say high perf

The "high perf pass" casting is found on almost all Mark IV blocks even through the 1980's in one place or another, it essentially means nothing. I have one 435 HP block that says "high perf ass" NOW THAT'S RARE!
Mark