If you just want to fly for fun the "Quickie Rat" thing is about the best idea. Be aware that the engine is built to turn high REVS on a small prop and a pressurized fuel system of some type.
Might be fun but it will likely be a pain in the tushy to get together and going! There are Rat Racer and Speed folks around that can help with advice.
Bill Bischoff and Bob Whitney above would be two likely candidates to listen closely to!
Randy Cuberly