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Re: 915 and 516 CC's
[Re: JohnRR]
#1604297
04/08/14 08:55 PM
04/08/14 08:55 PM
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Joined: Feb 2005
Posts: 4,318 Prospect, PA
BSB67
master
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master
Joined: Feb 2005
Posts: 4,318
Prospect, PA
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Quote:
Quote:
Both sets are now cut. Thoses were measured originals. Since then, one has had a valve job and cleanup cut and the other new valves and a cleanup cut. Cuts were about 0.010". They now measure 77 and 78.
Interesting .
Anyone know what ACTUAL piston to deck is on a 67 440 ? I'd like to do some math to determine actual compression ratio vs. claimed.
And no NHRA spec Deck to piston is not correct .
Piston CH is 2.002" Distance below deck ranged from 0.073" to 0.086" Driver's side averaged 0.085", passenger side averaged 0.075". #2 rod was 0.003" longer than the rest. My notes say that the head gasket measured 0.022".
I just measured the lower cylinder bolt flange thickness: 0.989". So if you believe that it was 1.000" from the factory, it apprears I had 0.011" cut off, verses my estimate of 0.010".
As I think I have mentioned in the past, a decent rule of thumb is 2.00", 2.03", and 2.06" for 67, 68 and 6 pack pistons. They were about 0.080", 0.050", 0.020" below an uncut deck respectively.
Remember, a valve job will add 1 or 2cc to the chamber volume. A hack job could add 3 cc.
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