Car won’t start but 12v at the starter

What is your question?

I recently put new pistons in the bottom end of my motor. Got the motor back together and put it in. Had trouble getting it aligned with the tranny. Car would hardly turn over like it was in a bind. I Ended up dropping the tranny and remounting it. That time the clutch felt better and I could manually turn the motor by hand pretty easy unlike the first time. Well this time I got it turned the key and nothing. I checked the crank sensor and all the plugs on the transmission. They are all plugged in and I have 12v on one post of the starter. Strange thing is I can’t cross out the starter to make it turn over. I also checked all fuses. Is my start toast or did I miss something plugging stuff in?

How long has your 1998 Ford Mustang had this problem?

Since replacing motor