Screaching from behind balancer

On the cheap, remove the fuel pump and put a bore scope in there and see what is going on.
They are like $35 bucks from Amazon and use your smart phone for a screen.
They work amazingly well, I bought it to see what pistons were in an 72 340 I bought, score, it had dome pistons.
The bore scope is cheaper than tearing it down, and at the same time you can pick up a new fuel pump gasket, they are the same as a small block chevy.