Alternator

[ShinyC10]

1986 c10 p/u

I have attatched a few pictures below. The wiring diagram is my setup no down to the T with exception of the BATT connection. I have a single 4g wire going from BATT to a 40amp maxi fuse and to the jblock. Recently, that 40amp maxi fuse blew and keeps blowing fuses every time I turn the truck on. The initial problem was the BATT stud was somewhat loose on the inside of the case so I opened it up and replace it with another stud from and old alt. The seemed to fix the problem till I drove it then it blew the fuse again. Got back home, popped the hood and put another fuse in and ran a few tests (remaining pictures in the post) and all of them show way higher numbers than what I wanted. Next step, I did a short test with a test light. Took all the fuses out and nothing seemed to be shorted out till I pulled the power accessory circuit breaker (little metal like fuse on the top right of the fuse box). That seemed to turn the test light off. I'm at a loss and need some insight.