Missing or incorrect dampner is the major cause behind failed oil pump. If the crank snout isn't properly counter-balanced, the oil pump gears will suffer.

Some engines are internally balanced, some are not, therefore, UD manufacturers do not always include a dampner, or, advice about them. If the Mach I owners are trashing their oil pumps, most likely it's because one owner used an incorrect set of pulleys and everyone followed his lead rather than making their own decision. This is an underlying problem with user boards like our MM.Net here. One guy does something, everyone jumps off the same cliff.

Best to check with a pro engine builder, and see which set of UD pulleys are correct for your applcation. Our shared 4.6L DOHC is not internally balanced, and a dampner is absolutely necessary. That said, you have a few styles and weights to choose from, some of which are NHRA certified for racing use.

If I were to go shopping for UD pulleys today, I'd buy the Steeda set from Reinhart. Many of us here have, with no complaints.