Preferred Underdrive Pullies?

I have to admit....I didn't read all of that. To be frank, like trinity, the back and forth between us going over and over the same points has pretty much exhausted my taste for the subject. He's going to have his opinion and I'm going to have mine.

Take note.....many...many Mustang, Ford, GM, Mopar, Import, etc owners have and continue to run underdriven pulleys on their engines with zero negative effects. Are there changes made to the amount of tortional vibration the engine is producing/seeing. Quite possibly...even quite probably. My argument is that based on the success of said aftermarket U/D pulleys, that these changes are insignificant.

Factory components IMO are rarely built with superior quality or craftsmanship in mind. A lot of them aren’t even designed to keep warranty claims low. They’re designed more often than not to provide quite, comfortable, smooth, trouble free operation over a vehicles lifespan in order to satisfy a wide variety of customer demands. This however is not to say that they can’t be improved on, but Ford isn’t going to take that direction because in some cases it compromises functionality and/or comfort. Underdrive pulleys have been known in some cases to reduce charging ability or ones alternator, reduce low flow capability of your water pump which in extreme cases might affect cooling ability in high heat, or stop and go traffic situations and may even slightly increase steering effort and A/C effectiveness in some cases. These are all things Ford isn’t willing to compromise. Your average hot rodder on the other hand has chosen to find ways around it. Smaller alternator pulleys to increase charging, cooler thermostats, or radiator upgrades or even electric water pumps to increase cooling (although I’ve never seen the need for it). And bumping the idle to cure most everything else.

But please don’t be fooled into believing that OEM will always signify superiority. Here are a few examples of OEM superiority for various vehicles….











I’ll tell you right now. Ford will always choose quiet and comfort over efficiency, economy. As long as it will hold out for the duration of the factory warranty, without customer complaint, Automotive engineers consider it a victory. Anyone who’s ever driven a vehicle with a sloppy factory equipped automatic transmission will be able to attest to that. But that doesn’t mean that by dipping into the aftermarket offerings, in attempts to improve on the factory design implies that you’ll be trading reliability and longevity for immeasurable performance in the process. There are far too many high mileage bolt on Mustang running the roads today that dispel that theory.


I’m not a Ford engineer, and I don’t design electronics for medical equipment (although I’m not sure how that would make a person any more, or less qualified). I’m just your average shade tree mechanic hobbyist. The son of a now retired automotive tech (that specialized in transmission repair) that spent 50-years of his life in the trade and who was highly regarded by many to be amongst the best in his field. That’s a pretty large shadow to spend your time in as a youth and I’ve spent a good portion of my formidable years trying to live up to that legacy.

I’ve spent my entire life working around Ford vehicles and most of my 20’s working in various capacities for a local dealership during the heydays of the 5.0L and 4.6L revolution. I don’t claim to be an expert in the field, but I do have years of experience with these engines and drivetrains under my belt, having gone through them from oil pan, to air cleaner on more than one occasion. Also, don't be fooled by someone throwing the word "Automotive Tech" around as part of their title. I've got more practical experience that a lot of "Certified Ford Tech's" that I've come across, many of which IMO don't know their ass from their elbow and should be considered nothing more than glorified parts changers.

On the other hand, a good "Tech" is worth his weight in gold and it’s a shame more dealerships don't appreciate and work harder to keep these guys around. Many of the shade tree mechanics, or independent "mom and pop" business owners used to be Tech's at one point, but just couldn't put up with the corporate structure, the flat rate and subpar wages any longer.

For my personal experience, I've developed a pretty good sense of what works and what doesn’t over the years and my own accomplishments and failures are proof of this. If someone chooses to take my advice, then know that I don’t give it as some off the cuff afterthought, without any practical experience or research being put into it. If you choose not to, then that’s fine too. It’s your car and your money. Drive and spend it however you’d like.