Bill, if you go back a few years, MAN ran a .60 engine ShootOut and the Fox .60 won it handily followed closely by the LA .65. I run a Graupner 12x8 on my Fox .60 which it turns at 11,000 rpm on Fox 5% fuel with 20% castor lube. And, if y0ou'll notice, the engine is nearly electric motor smooth. The Fox bested some fine engine in that shoot out.