The crank pully procharger sent me had no index I had to turn up a pilot so it would run on center

And yes the braket was way to light for the task at hand

I know there a lot of fans on here of the centriugals (procharger/vortec) but I would stick with roots or whipple.2c

I also have a 12 rib and I have shimmed the crank pulley.. I have not had a belt issue yet (only dyno time). I was just curious if anyone had made a belt guide. I have spoken to a few with Procharger that have had real issues with belts. I am trying to solve as many issues as I can before the motors go back in.

I am only producing 7psi where the guys with problem have been well into the double digits.

I don't think you will have any problems at 7psi. A lot of times chucking belts is a result of what's happening in the engine. Even the slightest bit of detonation will throw a belt, running on the limiter will throw or chew up a belt, valve float eats up belts, etc. On the prochargers the flexing mount definitely doesn't help but again @7lbs I wouldn't worry at all.

Ran the same belts 12 rib for 10 years over 300 hours at 7psi with no trouble . Changed them just becuase of there age.