The number that I remember for the piston above the deck in the HC 340 is 0.018". It could be 0.018" to 0.020".

The racing series limited engines to 5 liters. A Mopar 4.04 bore and 2.96 stroke comes out to 303.55. The sanctioning body allowed destroking to get the displacement. I remember sitting in the infield at Brainerd watching the cars, including the 1964 LeMans that some very smart crackpot was racing. That was racing! Cars that looked like cars you could buy the next day lumbering around the track (compared to the purpose-built racecars they were not graceful). And there was a turbo BMW 2002 that let out a huge blast of flame every time the driver shifted.

Remember that those engines used steel shim head gaskets. When Cab says to NHRA specs he isn't saying what he really means, that every dimension in the engine had to be changed to get to that compression ratio. That's the difference between the blueprint specs and the way Chrysler actually built them. On a 340 cubic inch engine to get 11.5:1 compression you need no more than 66.4cc above the piston. When the stock heads came in at somewhere between 68 and 73cc something had to give.

R.