Upgrading stock 1971 318 heads

Don't know if this posted correctly so I'm trying again............

The reason I asked about the year of the block and heads is that after '69 the 318 compression ratio kept dropping. It was 9.2:1 in '69 then 8.6:1 (more or less) in the 70s. I believe my pistons ('69 Barracuda) were .030 down in the hole at TDC. Your pistons (if it is stock) should be .060" or even .100" down in the hole at TDC. If your engine is a stock '71 318 you would have a hard time getting your compression any higher than 9:1 by changing the heads. It's pretty easy to check your piston depth before you do anything else. According to my Mopar Hot Rod Book the piston pin height was 1.77" in '69 then from '70 to '72 the pin height changed to 1.74". That means that your pistons (if they are stock) should be .060 down in the hole?? That's .030 (my piston depth at 1.77") plus .030 more for the change in pin height in '71. The problem is that someone might have changed the piston is the last 50 years??? So check your piston depth at TDC, this will tell you how low you can get you combustion chamber CCs before your compression gets too high. I don't think, if you have stock pistons you could cut the heads enough to get in trouble because 318 "stock" piston sit too deep in the bore??

Treblig