Bob, (fiat), we too have had problems with the manleys breaking. I refered to the additional weight in the rotating assembly as a fact. When we switched this time,(away from 6 usable Manleys), we lost 97 grams per rod. Multiply that X8 and thats alot of mass to get rid of. I'm not saying they won't spin up, they will, but running 7500 plus for 5 miles takes it's toll. Buzzing a motor for short distances is not really a good test, even if its a 1/4 mile, it aint the same...............Ray