Id get the new engine that comes complete and ready to run,,,break it in gently,,pull it apart and mod it with a 3rd port,,5 windowed piston,,performance porting,,polishing in key areas,,lightening the flywheel,,adding a rocket key and modding/lightening the clutch,,modding the reedstops,reedplate,,adding a composite set of reeds,,adding a pumper carb retrofit kit with hp airfilter and velocity stack...The stock cylinder has potential to belt out atleast 3 times the stock power with a simple dremel and some time / labor........The $79.00 engine from BigmotorSport offers an all aluminum pullstarter and velocity stack w/hp airfilter on carb aswell as free shipping.......
Even if you bought the hp cylinder kit youd still need a pullstarter and a coil leaving the old lowerend condition a mystery..........Good Luck