Jeff,
I had the same experience when I put on my high torque starter. I checked and double checked everything. I even ran a thread chaser (I think that is what is called) through the hole to make sure the threads were not messed up.
I eventually just ended up using two bolts instead of one bolt and one stud (that's how mine was set up orginally when I bought it). Why a bolt would thread and the stud would not I have no idea, but the pitch and diameter of the stud and the bolt where the same per my “Snap-On” pitch gauge set.
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