Repro. fan belt question

[ijg4503]

I was wondering if anyone has used the repro Mopar fan belts that YearOne is selling (Quanta Products). I have put 2 new ones on my 70 340 Duster non-A/C car and they have both done a snake belly roll on the pulleys. The first one came off and the car overheated and messed up my pulley paint. The 2nd one (tonight) just rolled and didnt come off. I have rechecked the waterpump and alternator pulleys for proper alignment and they look pretty even. I just shimmed the alternator again tonight even though it was pretty close already.

Any input would be appreciated.

Thanks,

Jason

 

[1968FormulaS340]

1. Your pulleys are out of alignment or damaged.

Or...

2. The belts are crap.