welcome to the forum rebuilding your engine would be the least cost, but if you want to build for hp, you can put in a k2 with a supercharger = 300 hp. but you have to replace the front engine section to fit and hold the bigger stronger engine. or swap to a b style engine, duel cam.. places i've been advise to order performance parts were : carid ( our on line sponsor ) summitracing, mugen, king motor sport, carspartusa. good luck in your eng mod.