I've been wanting to change the gear ratio in my gearbox from the 80 hp 2.27:1 to the 100 hp 2.43:1 in order to get a little more crankshaft RPM. Last Sunday I had the opportunity to finally do this.

I got a gear set from Hal Stockman and a slipper clutch from a parts engine a member of my EAA chapter had, so I proceeded to take the gearbox apart to re-shim it and change the ratio.


I found a little more than I was expecting...