[RichardJ]

Weren't those pulleys used on the C40 and larger trucks. They used extra groves on the air compressors (2 belts) for air/hydraulic brakes and the alternators had double belts as well.

I looked back through your build thread and I don't know what to say. You added a bunch of stuff that was never on a '67 C10, but it is ALL GM and close to the same years. Some things are very innovative and unique, but some left me scratching my head.