I have a 305 motor that was out of a boat and was wondering what info would be needed to see if these 305 heads would work on a 350 or a 400. The motor froze and cracked the block but I would like to reuse the heads on another motor. Also, does anybody know if I was to weld the 305 block back together if it would be worth using ?? I don't think boat motors have pressurized coolant systems like cars because it simply pumps water from the river and right back into the river. I am looking for a 350 to put back into the boat but if possible I would like to reuse the heads to cut costs. Any info would be appreciated. Thanks.