well i was wanting to build the shit out of it with a big blower and two carbs. i got a 2 bolt and its bored .060 over. i love the hp it puts out i just want to build a 4 bolt main. Or, even better, you can buy some splayed 4 bolt caps and drill your block. It's stronger than a conventional 4 bolt block, but the caps are expensive, and the labor is expensive because the holes have to be drilled at just the right angle and line bore needs to be done.