Alleycat has not been on this forum since June of 2013.
I've returned to Team Buick. I got booted off, looks like some sort of 'puter problem. Talking to one of the moderators, he mentioned that at the same time there was some sort of problem with other members. I couldn't even get on as a visitor, seemed to fix itself a while back, so, here I are!
Headers; I was trying to get Stan of "Stan's Headers" here in the area to make some if I provide something to copy. And, "you want how many hundred?" He is up to his ears with work... There's not enough hours in the day to fab 'em up one at a time. That said, the exhaust manifolds that come on the factory dual carb unit, are good, and with a little work can be made a lot better. Clean up and open up, the inside if the of the manifold where it bolts up to the head, don't hog it out, just clean it and make it a little larger than the port in the head. Where the exhaust pipe bolts to the manifold, don't just bolt up a 2 1/2" compression bent pipe and call it good, it'll work but it kills the velocity. Make a reducing conic, from 2 1/2" to 2". Make a venturi or a anti-reversion cone, weld it into the conic. Don't join the two outputs into one. 2" mandrel pipe, separate until down around the bell housing, collector. Nice as you're gonna get, short of a header. Alleycat
John Hemingway out in Cedar Rapids, Iowa, Had a set of manifolds cast, for the small engine. He was/is looking for enough interest to have a run . Price dependent upon number cast.
A few years ago, I was thinking about cutting down a 320 dual carb manifold in order to get a larger intake runner volume. I compaired the 248-263 exhaust to the 320, they looked to be exactly the same! Only the intake was extended to fit the longer 320. I did'nt do a breakdown bolt up to be absolutely sure, because I came up with a much better intake solution, but...Does anyone know fore sure if they are indeed the same? I can't walk out into the shop at this time to check for sure. It would mean that it's a one shoe fit's all. Alleycat
Back in the shop, after a long absence. I pulled out all my dual carb stuff, turns out, exhaust manifolds for the dual carb set-up are the same for both 248 and 320. So, in a pinch, a person could mix & match to come up with a functional set-up. Answering my own question. Alleycat