Thankx Mike, that makes perfect sense but this doesn't, small block chevy 434, 650 hp with a cast steel crank and a bad rod ratio, alu rods with light pistons, crank cut down to 40 lbs, this motor sees 8k for the last 4 years, I have drove this rail and seen the trap rpm so I know he is not full of it, and the crazy part is it was a used crank when he started, This goes against everything I have read about crank shafts, He has also built several engines for other racers the same way and they have not failed , Is this just dumb luck or is there more to bob weight than meets the eye? I read the cast stroker post the other day and have seen all the failures and opinions from the guys on here and tend to agree with the reasoning that cast cranks don't belong in race engines, But it seems to work in chevies?