ok, im having some work done on my engine, any the guy claims that ive been running my 100 over motor (66.5mm) with a stock head (64mm) and it is impossible that it even ran. It has run great for about a year now! he suggested there was thicker gaskets, but there wasnt. Is this just a really lucky case or what?? im sending the head to get shaved to accomodate for my 66.5mm pistons for the proper fit. What do u think is going on here, it has ran great forever like this.. I did notice the piston had some very slight markings on the top from hitting the head. what should I do!!!?!?!? thanks for the help. ohh, any cheap ways to solve this would be great!