Built 360 Having a Tantrum

I will stick my neck out a little and do the thing you aren't supposed to do and assume you are a female. With that in mind, you have quite a mechanical vocabulary, very unusual/refreshing. Since it sounds like this engine was extensively modified before your boyfriend got it, any diagnoses are going to be just guesses. Sounds harsh but I would pull it out and find out what I've got with a tear down and thorough inspection. Who knows what you will find??? Could be anything, could be multiple things. or you could just throw money at it and see what happens. That is the "typical" type of diagnosing a problem that I see most often.