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But like I said, that's best and I mean BEST case scenario. There was an acceptable variance in size in the block's deck height and specs of the crank, rods, pistons, so it's possible any of those motors could in theory be off by as much as .01-.02. I'm sure some 6 packs left the factory with dang near zero deck pistons, and some 440hp's probably left the factory with a piston .1 in the hole. Engines did not roll off the assembely line built to blueprint spec, so like was said, you really have to take a head off and measure the depth of your pistons and measure the CC's of your combustion chambers. Make sure to check several not all were created equal either.



i'd have to touch and feel these supposed engines with deck heights that are as much as .040 OVER factory blueprint as i have yet to find one, though i SEEN a number of people CLAIM this with NOTHING to back it up ...



edit ...

I just looked at NHRA blueprint for a 1970 440HP , advertised compression is 9.7, and the blueprint spec is .051 in the hole. As far as I can tell on the chrysler engines I have checked into NHRA blueprint is usually .020 HIGHER than the ACTUAL CH (the highest over being the 68-69 383 HP at .024 over actual). I would SURMISE that the CH of an ACTUAL 440 HP 1970 piston is 2.010 and the available pistons across the board at 1.991 by the AFTERMARKET is allowing for decking . The ONLY MAINSTREAM BB aftermarket piston that I have found to date that is the SAME as the factory PISTON it replaces is the 1970/71 6 PACK piston ...

YMMV

Anyone have an ACTUAL 1970 440HP std. bore CHRYSLER ORIGINAL piston they can measure the CH of , I would really like to know what it is ?

THANKS


Last edited by Johnrr; 07/03/08 05:41 PM.