wow,posted the question,went to carlisle and, BOOM !!!!!!!!!!!! lol i completely understand about the balancing thing. after building the steel cranked 340 I'm currently running{7 yrs and counting since last rebuild},the question I should have asked is what will happen when I go spinning a 418 up to 6500 rpm on a regular basis????,the car will take it 727,dana,spool,etc