Building up my 68 340

crackedback said
Stock 340 might say it's 10.5:1 compression. Reality, it is closer to 9.5:1

Or it might be 10.3:1 , back in the day some 340 Darts were faster than others from the factory , the machining and assembly back then was not great compared to today , todays pistons and rings are a big improvement over factory parts .