Just found out that my 305 block has 3 cracks in it where the previous owner or soembidy over torqued the head bolts. The machine shop said it can not be fix. This block is a 1 piece rear main seal. He has several 350 blocks but they are of the 2 rear main seal. I know I can not use my crank which had just been polished (1 piece rear main seal) or can I? If I use the older style 2 piece rear main seal, can I use my 305 heads on it. I know what you are thinking but I just dont have the money for new heads. The cheapest around here for a core is 400 dollars. If I use the 2 piece seal block what fly wheel would I need

 

look for a 350, or 305, whatever you want and go from there. not much you can swap around and make an efficent package out of.