I was thinking an on-road engine too. Just swap out the front bearing to a double rubber shielded one and your good to go. But would this work? I mean other than power characteristics and the cost difference what actually stops someone running an on-road engine in a buggy? The on-roads are built for constant 45,000+rpm pounding's. They do run 2 speeds though, buggy class can not.

Tell you what though if there was ever a track that engine power mattered it would be this one. Best engine and tuner wins on this track!