I picked up a disassembeled sb400 for free. It's been bored .030 over already, has 76cc heads, stock cast intake, q-jet that definitley needs rebuilding, and some other crap. Is it worth even rebuilding? If i did it would be bored .040 over. I already have a good running rebuilt 355 in my truck. Would this engine out last the time and money spent rebuilding it?