Note that a standard HS cam (modified or not) is going to reverse intake and exhaust, and the engine will run like that, (I have one with a keihn carb sitting there) the exhaust porting is way small on the H35. I'm only chiming in with that, because we've talked about the "Bungholio" engine, and when I built one, I noted the "now" intake was anemic- and so grinding the H35 cam as Delray suggests would be the best way to do it, not using one of the many HS 245 cams in existance.