340 compression ratio

Cause if the engine was built late in 71 ...it might be a low compression 72
IF STOCK PISTONS, they will come up over the block. And stock CR on the early build 1971 340 is 10.25, where 1970 and earlier is 10.5? What I read somewhere...... My 340 is a late 1970, so I'm guessing it went into a 1971 car. Just guessing, when I get around to it I will find out for sure.