RE: cranking big gassers
Tower. Its about a 2 1/2" I think. Cone and insert both from Tower. I used a 5/16" allen head grade 8 bolt, anything less and it bends. Drill the cone and tap it for the threads and use a locking nut on the back. I have two, a smaller one for spinner nuts and domes, and the big one. I tried it on a quadra 70cc awhile back and it wouldnt start that one, it was pretty high compression. Havent tried it on my GT80 yet, havent needed to. We have a 84 year old guy in the club that uses a big sullivan with a miller gear drive to start big ones.
Edwin