NHRA Engine Specs

T

Tom H

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In viewing the NHRA Engine specs for 1971 it lists the compression ratio at 10.5 to 1. This was according to what I read elsewhere on the buicks.net web sight. Could someone please tell me if this is a misprint and should read 8.5 to 1 or is this really in the NHRA engine build spec book for that year.I'd like to build my 71 to NHRA Spec. but can't believe its 10.5 to 1.

Tom Hearsey
 
The 70 had 10.5 -1 and it was because they had a very shallow dish in the piston. If in fact they do allow the same in the 71, you will need to replace the pistons ,as the 71 pistons have a much deeper dish. The 70s were not really that high, but they were playing HP games then.
 
Yes Joe,if you go to the buick.net home page and go to buick tech, click on RACING. Scroll down to NHRA Logo - under Buick Bluprint Specifications 1971 list the dish on the piston as 28.7cc., head is 59cc, Gasket is .041.
Upon further inspection I find the 1970 at 10.5 to 1 But with 16cc piston dish, 55.5cc head, and a.020 gasket.So obviously just an error. Thought I was on to something that maybe NHRA would let a 71'n run with 70'compression spec.They carried that mistake on through to 74'. Oh well thanks anyway.
 
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