I just bought a 1990 550sx and 2 of the head studs were broke off in the crankcase. so i took the head off and was extracting the pieces when all of a sudden it created two hair line cracks on its way out in the crankcase.....

So now i am contemplating on buying a new OEM crankcase for $325 instead of JB welding it or something just so i dont have problems down the road.. but my question is do i have to buy a crankshaft rebuild kit? or can i just use the same stuff that came out of the old one?im trying to go the cheapest route possible. and if anybody has any good suggestions please let me know.. Thanks
ALSO IF ANYBODY HAS A USED CRANKCASE THAT IS IN GOOD SHAPE FOR SALE LET ME KNOW