Had SBT motor was 1.00 over. One piston took a crap. I beat the crap of it day before . had perfect piston wash next morning, my daughter was driving half throtthle with both of us on it when it start ed to burn. Looks like fuel pump was the culprit "oring gasket was not in right". Looks like i can go to 1.5 mm over , has CV carbs will i have to rejett. Is it nessasary to bore all 3 to 81.5.,