is there a way to test compresion? i dont thik i had the power in my F4.1 that i used to. when I had the engine out and turned it by hand there was slight hiss (through exhaust) on the compession stroke. I'm assuming thats bad compression????? also, is it worth it to buy the piston and sleeve and rebuild? will it run like new or are there more parts that need replaced? or forget rebuilding and just buy a new one? pretty tight budget here. thanx guys