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Alternator Pulleys- V-Belt
Pontiac V8 Alternator Pulleys- V-Belt
Small Pulley, Big Effect — Alternator Pulleys- V-Belt for Pontiac V8s
The alternator pulley is the smallest pulley on a Pontiac V8 and the one turning fastest, so it sets how hard the charging system works and how much the belt has to hold at the top of the tach. Swapping it is also the simplest way to slow an alternator down on an engine that spends its life at high rpm.
Butler stocks Ram Air Restorations single groove pulleys in billet, gold and black finishes including a 5.0 inch underdriven version, along with the March single groove pulley supplied with a billet cover and hardware.
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More About Alternator Pulleys- V-Belt
1. Stock diameter or underdriven
Alternator pulley diameter is a gear ratio. A small pulley spins the alternator faster off idle, which is what a street car with a big stereo and electric fans wants. A larger pulley slows it down, which is what a high-rpm engine wants so the alternator is not overspun at the far end of a pass.
| Stock diameter single groove | the direct replacement for a factory V-belt front end, offered in billet or gold finish. Use this when the charging system works and you simply want a pulley that runs true and looks right. |
| 5.0 inch underdriven | a larger pulley that reduces alternator speed for a given engine speed, in billet or black. This is the one to reach for on an engine that revs, or where belt squeal and alternator noise show up only at the top of the range. |
| March single groove with cover | a 2 11/16 inch pulley with a .667 inch bore that comes with a billet pulley cover and all mounting hardware, for a cleaner finished look on the front of the engine. |
2. Fit, alignment and what else to check
Alternator pulleys are not universal even when the belt is the same width. Check the shaft bore against the alternator you are running before ordering, and confirm the groove depth matches the crank and water pump pulleys already on the engine. Deep groove billet pulleys hold a belt far better than a worn stamped pulley, but only if they sit in the same plane as everything else driving them.
Not sure what your Pontiac needs?
Call our tech team at 866-762-7527. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.