97 lt1 head casting numbers?
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Joined: Feb 2006
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From: Port Charlotte, FL
97 lt1 head casting numbers? What is the difference in the 643, 374, and 561 lt1 head castings?
I was planning on doing either an AI 190 or LE2 heads and cam package, but AI wants the 643 or 374 castings for that set up (LE does not specify on his site). I have an lt1 out of a 97Z with the 561's. What years had what heads and what is the best performance that I can get out of the 97 head?
I was planning on doing either an AI 190 or LE2 heads and cam package, but AI wants the 643 or 374 castings for that set up (LE does not specify on his site). I have an lt1 out of a 97Z with the 561's. What years had what heads and what is the best performance that I can get out of the 97 head?
Can't tell you which casting numbers match to which years but I can say that the 97 heads flowed slightly better stock but have less material to work with for porting as far as I know. Hopefully someone more knowledgeable will stop in with the information about which castings go with what years.
Edit: I had my 97 castings hand ported by a local shop in Houston and was very pleased with the results, they all flowed within 1-2 cfms of 290@.600
Edit: I had my 97 castings hand ported by a local shop in Houston and was very pleased with the results, they all flowed within 1-2 cfms of 290@.600
