buy a steel crank, new rod and an oversize piston. balance the rotating assembly. if you can find the rare kohler governor weight assembly put that in. put the 30 lb flywheel on it and a heavy steel starter pulley, put a cam in it, mill the head till there's about .050 between the top of the valve and the head when the valve is open. playdoh or bubble gum works good for this. advance the ignition timing , deck off the top of the block till the piston is flush with the top. if an adjustable cam gear is allowed do that and advance the cam timing. a good valve job, dyno tune it to its optimum , dyno tuned exhaust pipe, a little fine tuning in the carb . should be a pretty stout motor. for a fuel pump I'd use the kohler mechanical pump,
you will then need the finespline rear. and a good clutch. put a 15-17 gearset in , lower pinion retainer, weld up your shift forks so they don't bend. run it at a few pulls and then if you need a faster gear then you can toss a OD in.
if you don't have a clue how to do this then just send it to someone who does with a blank check or a box of big box of cash . otherwise its just trial and error and allot of beating your head against a wall
