I had a friend who put a 40 sized aircraft engine on an old RC10 chassis long ago and it was the fastest thing I'd ever seen in RC. He mounted the engine on a homemade pod and used a three bladed prop for clearance. He could only run it in large mall parking lots because of the speed involved. I'd bet the farm that he was pushing 120 or better flat out. I don't remember the pitch he was using. The car died quickly when he made too sharp a turn one day.