I fixed my busted HB/pulley for about $5. I couldn't justify $400 for a damn pulley. My fix would be considered a hack job by many folks but FWIW, here's how I addressed the issue: First, I used a punch and knocked out what was left of the rivets. Next, I tapped the holes in the HB for grade 8 bolts and bolted the pulled back onto the HB. I used bolts that were long enough to get a nut on the back side of the pulley. I had to be extremely careful not to use bolts that were too long for fear that they would make contact with my timing cover once everything was bolted up. Once I determined that clearance was not an issue, I tack welded the bolts and nuts to the pulley and HB. Finally, I welded the pulley to the HB with three equally spaced 1.5" beads around the circumference of the pulley. I placed the finished product in my drill press and ran it on the highest speed to check for any vibrations or wobbles. It ran true. I reinstalled it and I've been running it for several months with no issues whatsoever. It runs true on the crank...truer than the other pullies do, actually.
In my way of thinking, the pulley is solidly bolted through the now threaded holes in the HB. If all the nuts came off the back, chances are the pulley would still be held firm against the HB by just the bolts. Counterpoint: If a nut falls off, it could mangle the timing cover. Counter-counterpoint: The bolt heads and nuts are tack welded into place. Barring some sort of major catastrophic event, they aren't going anywhere.
Welding the pulley to the HB was a difficult and potentially risky decision. I am aware that welding metal over rubber is not a great idea. That's why I only ran three small beads as opposed to running one continuous bead around the whole pulley. It didn't seem to affect the rubber at all. I never even had any burnt rubber smell. Nothing smoked, smoldered, bubbled or caught fire. I just wanted the extra security of knowing that if all else failed, the HB and pulley would remain as one.
I was worried about balance being an issue with the bolts and welds and all. It doesn't seem to be causing any problems. The pulley had obviously been wobbling and working itself loose for a long time. It had to have been out of balance while that was going on. My engine didn't explode. My crank didn't break in half. Nothing happened. The balance of a 2F rotating assembly is not great anyway. The crank is stout. Hell, the whole bottom end is built like a tractor. I honestly don't think I'll have any issues with my el cheapo HB/pulley fix. If I do, I'll let y'all know.
