1970 340 has the 1973 low compression pistons

You are so incorrect, it's not even worth the time to correct you.
Why not you blast Everyone's else post. You think you are the guru of everything Mopar. Last time i checked 1 point of compression on a STOCK engine was 10 hp . Ive seen it in action. 10 horsepower equates to 1/10 second, these are not hard fast rules but approximations.. Look it up for yourself.