While driving home after a long weekend I hear a loud pop followed by reduced power, a lot of vibration and loud clanging sounds from the engine. Not good. Pulled the valve cover, everything looked good. I turned the motor on and the oil was comming out of the rockers but quickly turned it off. The sound from the lower end was a tinny clanking sound. I have not had the chance to pull the pan yet to check the bottom end or check compression and won't be able to until next week. With that said, here is my question. I have found a motor out of a '70 fj55 for a good price. Are the heads, manifolds, accessories, brackets etc interchangeable between this motor and my f motor in my 12/74 fj55 (late model f). I didnt really pay attention to the differences when I saw the motor because I wasnt in the market at the time. The one thing I did notice, was the oil fill. Mine is on the valve cover and the other was on the side. Any help or search ideas would be great. I don't want to just drop in a V8. A diesel would be nice!!!!