I am in the process of deciding which aluminum head to upgrade to and am need to know what combustion chamber volume to specify. I know my car has TRW L2416F30 pistons with an 8.5cc dish that the previous owner used to drop the compression down with my stock '71 (63cc) heads. However I can't find any specs for that piston except for the dish volume. I really need to know the exact compression height. One post indicated a height of only 1.610" where a stock 351C piston is around 1.650". If the TRW replacement pistons actually have a 1.610 compression height that leaves me 0.060" deck to piston distance (9.2-1.61+5.78+1.75 = 0.060). Using diamond pistons comp calculator, and guessing at a top ring down of 0.265, I end up with weak 8.8:1 compression ratio, and would need to drop the combustion chamber down to 55cc to even get 9.5:1. I would like to go a little higher with the aluminum heads and my 4000'+ altitude. 55cc may be too much to ask for. Not even sure the replacement heads can me milled to that. I know I can pull a head and measure the distance, but was hoping to get the new ones here before I started to tear down the motor.
Any data, advice, or corrections appreciated. Thanks, Evan
http://www.diamondracing.net/tools/
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