Once again, are you going to build a slightly modified motor, or are you stroking it out, going w/straight cuts, hinson basket, override tranny, pancake bearing, cub cyls, etc.... If you are just building your typical slightly modified shee(pipes, air filter, maybe advanced timing, reeds) then I would look for something complete. By time you piece together every nut, bolt, seal, gasket, gear, etc. you will have spent way less money buying one complete to start with.