[mrein3]

Originally Posted by 67ChevyRedneck

GM had so many variations of pulley combinations it's ridonkulous. Single, double, triple, quadruple, A/C, no A/C, P/S, 2wd/4wd, small block, big block.

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I fought and fought and fought with issues on my truck with pulley combos for years. What happened to me was under certain RPMs, the alternator belt would set up a vibration that was actually quite wild and would eventually snap off the alternator mounting bracket. Which on a truck without AC also takes out your water pump. Which is bad. (I added AC later).

What I finally ended up doing is getting a FULL set of pulleys off of a truck that wasn't bastardized by one or more previous owners. Since I was planning to add AC I made sure I got them all off of a truck the the general made with AC.

That was over 10 years ago. I have never looked back.

Long story short, watch the parts board for a fresh part-out and ask to purchase all the pulleys on the water pump and all the pulleys on the crank.