I believe that the speed guys made them go but not without a lot of work. I think the OS 65 VFDF was a good candidate for rework for D speed. There arent very many around and speed timing is not from a standing start like carrier. The 10CC bypass Rossi's had a lot of torque and so did the Tigre G series 40 and 65.
Wayne

The old by pass 10cc Rossi's worked like a charm. Dont know anything about todays Scnuerle port Rossi 60's.
Wayne

Mention is made of the OS 65 REDF, perhaps they are more easily found than the Rossi. I've flown the same MO-1 with my OS65REDF at the Nats in Class II for at least ten years and recommend it highly. Bill Bischoff converted it to reverse crank confiuration and I use the APC 10x6 pusher prop with 50% Magnum fuel. It is a mild mannered motor, I've done nothing but fly it. It usually gets about a hundred mph, plus or minus and has placed 2nd at least three times, third maybe more, at the Nats.

Mike Greb used the OS 61 of a few years earlier design, again, reverse rotation with similar results. I'm listing one of these in the Classifieds,

Respectfully submitted,
dale g

Edit: As to the high idle speed, I find that a desirable feature....in the hang, if the engine is "spooled up", the throttle response is immediate, so it's there when you need it. But, I'll have to admit, I can't remember ever taching my REDF, either high or low. My guess is that it is about 17K high and around 6K at idle. I'll be sure and check that next time I fly it.