Another board was lit up after the Knoxville nationals regarding the winner pumping too big...apparently they pumped 7 times before it showed legal...un-involved motor builders explained that aluminum engines will pump slightly bigger if pumped when hot due to metal expansion and that once the engine returned to atmospheric temp, which is what the rule states, the engine in question was fine...I would ASSUME something similar happened to the Clausons, and the bore and stroke test is the only true way to determine displacement.