I've done a lot of carb rebuilding over the years on antique and classic cars & trucks, (part of my business) and the viton needle & seat assembly really isn't anything new. They're still in quite a few carb kits for most cars & trucks. I stock the rebuild kits for the Zenith carbs on the AC's as well. The one's I have on the shelf are made by Dana, which I believe is one of the subsiterary companies of Napa/Echlin. You can probably pick one up at yer' local Napa dealer. If you have trouble getting a kit, drop me line. They're very inexpensive... Steve B.