Magnum gurus needed

It has the wrong balancer on it if it was internally balanced. It has a later external balance balancer in it. The scallop out of the front of it indicates it is an externally balanced balancer. So, that means one of two things. Either it's stock externally balanced, OR it has the wrong balancer if it's really been internally balanced. I don't believe it would be possible to internally balance that engine with that particular balancer, as it is for an externally balanced engine. I think you need to find "what is what" before you go any further, even if you have to disassemble it and take it to a competent machine shop. Otherwise, it may well disassemble itself. That might suck.