I chose a RCV-120 because it fit easily in the cowl and turned a 4 blade proper in my GS Spitfire. My son is building his first warbird, also a Spitfire but a TF 60 size and also chose an RCV all be it a 60 for the same reasons. We just bench ran the motor last week and the sucker ran forever on a tank of fuel and we ran it very rich. Be forewarned though, you need a STOUT starter undil the engine is broken in good.

David