MustangGT 11 Report post Posted September 5, 2013 Went to the local auto parts store to replace my tired alternator; when looking it up in the system he gives me the option to get a little more amperage than the stock one. He said since the car had A/C it would better to run the higher amperage. He didn't have it in stock and had to order in. Well, went to pick it up and the alt came with a double pulley installed - my old one only had...you guessed it one. I couldn't do a pulley swap in the store since the PO had welded to the alt shaft. I have seen in the Osborn Engine Manual my 351 did come with a dual pulley (depending on options). So it isn't out of the ordinary. However, I am not sure about 2 belts on an alt in my compartment. Can I switch to a single pulley without affecting the performance of the alt or should I just suck it up and run 2 belts. Thoughts/opinion/suggestions welcomed... Quote Share this post Link to post Share on other sites
LindenBruce 27 Report post Posted September 5, 2013 As long as you are running a wider belt, in Goodyear for example it would be a 17 series belt, you will be fine with one belt. You can also change out the pulley to a single belt pulley if you like, but you will need to buy the pulley. As long as you are not running an amplifier for a large stereo system the belt wont slip and squeal. If you decide to run a twin belt, make sure the belts are a MATCHED set. Otherwise one will be tighter than the other even if they are the same part number. B. Quote Share this post Link to post Share on other sites
buening 63 Report post Posted September 5, 2013 The trouble I've found is finding a crank pulley for a 351 that has two equal diameter pulley sheeves for the dual belt alternator. The 2 and 3 sheeve crank pulleys have different diameters, with the second for the water pump and PS and the third sheeve for the A/C. Quote Share this post Link to post Share on other sites
MustangGT 11 Report post Posted September 6, 2013 I hadn't actually thought about the problem with the 3 groove crank pulley. I have only roughly installed the A/C (new Classic Auto Air Bracket), power steering pump, alt and crank pulley. Didn't have water pump pulley connected. I just re-looked at it and I could run it with one belt but that empty pulley would look so bare -- I don't think I handle seeing it every time I lifted the hood. So I guess I will have to switch out to a single pulley. Just when I think I am done spending $$$ on the ol' girl she takes a little more out of my wallet. :cool2: Will look around for a used pulley although CJ has them for less than $30. Quote Share this post Link to post Share on other sites
dennyb68 11 Report post Posted September 7, 2013 I have that chrome one you can have back.You could paint it Quote Share this post Link to post Share on other sites
