Langdon's Stovebolt sells Carter-Webbers, progessive 2 barrells with electric chokes, and they work nicely for about $60 apiece. You've got to buy an adapter and linkage since I don't think the one that works with the leakchesters will work with the carter-webbers.

'51 Chevy 1/2 ton w/'62 261, HEI, offy, fentons, dual carter/webbers, t-5 & 12 bolt posi