now here’s another question, if it has a cast crank then is it externally balanced or internally, and if externally balanced do I need a external balance flex plate or converter. Guy I bought it from put different pistons in it and says it’s about 10.5:1 comp and that he had the rotating assembly balanced with those pistons, does that make it internally balanced now? Sorry I’m a newbie when it comes to 340s and I just want to make sure I don’t do anything to hurt this engine.