Spun through the search function, but did not find anything (but I will keep lookingt!)... So here goes... Buick 263, straight 8. Looking at firing order, looks like the 4 middle cyl's are essentially one even firing 4 cyl. engine, and the others (2 on each end) are another even firing 4 cyl. engine. Saw the intake on the "for sale" forum, and it looks like it is set up this way (as is the stock intake with the single 2bbl carb.). From the search, and other reading, it sounds like the end cyl.'s run lean due to intake design problems in any event. The problem is that my intake manifold is cracked (not totaled, but not good either) and I am looking for options. Seems like carb's would prefer to run under even pulses, so it would appear that it does not make sense to do a dual carb set-up if one serves the first 4 cyl's, and the other serves the back 4 cyls as the intake pulses are not even. I have seen pictures of a tunnel ram (I think) set-up with a common intake plenum with a separate runner to each (siamesed) intake port. Would go this direction if necessary, but would rather go with the 1234 5678 set-up with two separate manifolds, one front and one back. Has anyone tried this?? Would make sense from an expansion standpoint, but I am curious if it performed well. Thanks!
Why not go EFI?? It would solve all those problems. But the plenum would be the carb'd way to go, if you could fit it all in there. Probably have to have the plenum above the runners to help fit it between the fenders. Could be a bitch to start in the winter with all that plumbing. Like I said, EFI would solve all those problems... Even if it were a constant flow system it would be a huge improvement over carb'd.
I am building up a 263 right now and thinking about what to use... How about four 1 1/4" SU's and a balance tube? I would really like to do that except for the linkage nightmare I keep having about it. It would probably run & look great. Firing order doesnt seem to be that critical on these old siamesed port engines anyway. I will probably wind up with a log manifold and two 2 bbls. Simple to weld up. I do believe I will weld a coolant line to the bottom side for a little anti-ice help. Anybody got any pics of homemmade inline stuff?
Eddie Edmunds never thought about that kind of thing. Luckily its pretty easy to make a log-style manifold Heres an interesting design, the rest of the site is worth checking out for any str. 8 guy. http://gamma.nic.fi/%7Emarlin/april2004.html
Its a Packard, but he built split manifolds for it. He's running two Webbers on it. It runs pretty good set up that way (Its in a '36 PU now).
If your firing order is the typical 1-6-2-5-8-3-7-4, the problem I see with the 1234 - 5678 manifold split is that you have two adjacent intake events on 5 and 8. You rightly noted that the center four and outer pairs of cylinders look a bit like coupled 4 cylinders. Building an intake that had a carb servicing the center four and another servicing the outer two pairs eliminates that issue. Frankly, it's probably not a big deal, though. The same issue exists on most V8's with adjacent intake events on two cylinders.
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