If it's running block off's, I am sure the motor was ported for the block off plates. What size cheetah is it? Run V force 3 reeds in it. more commen to get a hold of the reeds. The 2"s will give you alittle more power around "2 hp". keep the lock up. its not going to hurt anything. No such thing as a HD clutch. There are HD springs. If u run a lock up with little weight on the arm's "10 grams" just run stock springs. your clutch hand will love you for it. or you can run 3&3, 3 stock and 3 HD. Not going to get into spring rates with you. What kind of ridding are you doing with this motor? Dune?,Hillshooting? 300'? 1/8mile? If its 73mm I can sell you PV if u want to try them out.