My street 518 C.I. low deck makes over 700 hp on pump gas, on what maybe a happy dyno, I bought the Mopar ductile iron main caps and ARP main bolts ad had them installed along with a align hone to make them fit properly. going on four years of racing some(400+ passes shifting at or above 7000 rpm, knocking on wood, ) and street driving some, 1200 or more street miles I think the key is to avoid detonation and look at all of the bearings every so often