Maybe Old Goat will see and comment on this, he did many of them, trouble is they broke cranks like they were candy. If I were doing it I would use a good electric oil pump such as the kind NASCAR uses to circulate oil for the rear axles. I rigged one up for a 9 hp flattie but changed at the last minute. You need to get oil moving around so the crank hits it and sends it flying, useing a regulat oil pump (brigggs padle wheel) would help if you squirted oil on it. Kenny (Tn.) did this on a 12 hp flattie and just used a fuel pump, he never blew it from lack of oil.