Deep Grove Pulleys

[alhewitt]

I was at a car show last weekend and looking at other 57's I see different depths in the; generator, water pump and harmonic balancer pulleys. The depth I refer to is the fan belt depth while on the pulley. Some pulleys have the belt riding high where the top of the grove is flush with the belt and others have the belt recessed into the pulley. I'm assuming the width of the belt will effect this but it was clear there are difference pulleys. In the world of 65 Chevelle's with the L79 engine they came with a deep grove pulleys. I'm including some pictures of my 57 and hope someone can comment on what I may have.
Thanks
Al

[BamaNomad]

I can't see much from the photos (out of focus?).. but your FI engine should have come with deep groove pulleys from the factory...

[alhewitt]

I apologize for the lack of clarity, this was on my mind, I went out to my garage and used my cell phone, what you see is what I got.
Is the deeper grove about higher RPM's? A method to help reduce throwing the fan belt?
Thanks
Al

[Rick_L]

I think you may have deep groove pulleys, but I can't verify that. I think the stock pulleys and stock belts will have the top surface of the belt roughly flush with the top of the pulley groove. Yours are offset slightly.

Deep grooves with the right belt will prevent belt throwing at high rpm. I had a problem with this many years ago and used Moroso pulleys that were deep groove and were smaller diameter on the crank and bigger diameter on the alternator, slowing the belt speed. That's probably not something you want on your car though.

With any belt setup, make sure that the bottom of the V does not touch the bottom of the pulley groove. Instant belt slip when that happens. Years ago my neighbor had a 4 cylinder Chevy car that had such a setup on his alternator, belt slipped. I put a pulley off a junk alternator on it and fixed it. I don't have a clue how it got that way, probably an alternator rebuilder's mistake.