How about an HP .60 four-bolt head schneurle ported engine? It is period correct, believe it or not, and it stands head and shoulders above the non schneurle ported engines that have been mentioned so far, power wise. They are not cheap on the used market, but they go like stink.

Don't forget those high nitro fueled .91 four-strokes that you will be up against.

Of course, I would rather stick with an OS .61SF side exhaust with muffler. It isn't period correct, but it doesn't have to eat even a tiny slice of humble pie when compared to the four-strokes.

Hey, Vince! Which OS is that? I can't read the side of the engine, but it looks like an OS FP of some size.


Ed Cregger