Get yourself a power probe tester.
ive used one for years as a pro mechanic....best thing i ever got for elec problems.

I disconnected everything but the battery cable and it still wants to turn over. I think it's an issue with the starter. I took the old one in the other day and got a new one as a spare. I'm going to put that on and try it.

Apparently I threw away the original bolts for the starter, or at least misplaced them. Either way I couldn't find them so I went to the parts store for new ones and took the hi torque starter. Had it tested and it was fine. Reinstalled it with no issues. Maybe I had the battery cable touching the other post on the starter? Not sure but I have one other check to do on the ignition switch before I'm comfortable saying it's good and installing the dash.

One step closer, glad you got that problem resolved.