So after changing the HG and putting on the timming belt. I baked the afx pulley at 400 for more than an hour and slipped it onto the crank. I tapped the center of the pulley to get it on further. I put on the crank bolt and started tightening it. It went on quarter of an inch and the bolt became loose. Now when I took out the bolt, the first 3 threads are chewed up, and the bolt would not go in any further.

wtf did I do wrong? and How would I go about fixing it?

You assumed three threads (about 1/10th of an inch of metal) were enough to hold about 400lbs of pressure.

Try finding a threaded rod or longer bolt to draw the pulley onto the crank.

This is a pic for attaching the crank sprocket, but the same thing applies for attaching a UDP. Just make the Red part long enough to thread completely into the crank (15-20 threads) and still have room for the UDP.

you definitly need a longer bolt. i dont know if its the same threading or not, but i used the passenger motor mount bolt. it is longer and, i threaded it in about 4-5 turns or so. It worked fine for me.