I was just trying to figure out if this machine has been bored before i just bought it about a month ago. From what I have read 64mm is stock, 64.5mm is 20 over, and 65mm is 40 over so I am guessing with the piston i pulled out with the numbers being 6475 it must be 30 over? I am planning on buying all new parts for this machine and was mainly wondering would it be worth the extra buck to start with the longer crank now and eventually get the porting done next year when i rebuild it again?