I was going to be a wise guy and say 10,000 on my lawn mower but only 1 on the top fuel motor, but i think you already get that concept. Had i kept the 4 inch stroke 440 deal with BME rods, i would have never worried about how many runs since the motor never saw more than 6200 rpm max. I would bet it could live for 1.000s of runs since the pistons were very light, 600 hp and low rpm. On the other hand i was told 300 by grp for a 4.41 stroke deal going 7500 rpm max. There has to be a way to figure this out better than just telling everyone a certain number of runs based on pretty limited info on thier use. My question would be beyond piston weight stroke, rpm and power level/type of power adder are there any other factors that play a large part in determining life cycle? Probably running temperature of the rods?