I had a telephone call when posting the above, and had to finish before I was finished.

Yar mentioned seals on Webers. I have done very few Webers, and since I am no longer restoring carbs, will never do another; so do not have a lot of knowledge about their construction.

I do know that Holley tried Teflon seals on throttle shafts on 4150's and 4160's for a few years, and then I believe they were discontinued. But the Teflon seals created a TREMENDOUS market for throttle shafts!

WHY?

The Teflon seals wore out in 20k~30k miles (we put the seals in our rebuilding kits for this reason). But to replace the seals, the throttle shafts must be removed. And do-it-yourselfers often would destroy the throttle shaft by twisting off all of the throttle plate screws. The old "law of unintended consequences". Some jobs are just best left to a professional.

Jon.

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