In post #52, it was mentioned about "Fat Fin Heads". That was Wayne Clagg, friend of mine that lives about 40 miles south. He put a large VW engine in his Zenith 701 with the belt drive. With all the bells and whistles on the engine, he told me that the engine weighed 235 lbs, if I remember correctly. Had heating problems from running the engine so hard. I think he said the cruise rpm was 3800. When he would fly up to my field, it almost sounded like a hi-rev Rotex. He was on his way to OSH in the 701 with about 80 hrs on the engine and the engine case cracked. Trucked it home and put a R-912 in it. The added fins that he welded on did help some, but no enough for the HP that he was demanding from the engine.