Firestorm - Engine suggestions
 

I'm looking to get a new engine for my Firestorm. I'm not too sure what to get though. I'm looking for something that will be pretty easy to replace. Maybe give a bit more power without having to change clutch or gears. Basically I'm looking for a new engine where the only thing I would have to replace is the pipe, engine, and get mounts for the engine. Any suggestions?