Playing with my carters today and a friend of mine has suggested that I try his dual holleys from a C**V Tunnel Ram he has lying around in his spare room. I said "I don't think the holley's fit on the Carter bolt pattern" Do they?
Bill, The Holley's come in many different shapes and sizes, so this is a tough question without any carb numbers. The bolt pattern is the same on some of the smaller Holleys and should match the Carter AFB bolt pattern, but that is just the beginning. The Holleys have front and rear mounted float bowls that would probably not allow them to be mounted length wise on the intake, they would have to be turned 90 degrees to get them to fit. Linkage then becomes an issue, although not an insurrmountable one, as some supercharger mounting flanges mount the Holley's sideways and I am sure that someone makes a kit for the linkage. Be careful of long sitting Holleys, they tend to have their float bowl gaskets dry out and shrink, and then they drip that nice premium fuel all over your detailed engine! Good luck on the swap, Tim McCluskey
OK, first off, the Holley bolt pattern is the same from front to back, but wider than a Carter. That said, the replacement Holley spread bores are the only Holley's that have the narrow width bolt pattern, but the rear throttle plates won't clear the manifold, as these carbs are the same throttle bore configuration as a Q-jet. Also, any square bore Holley will need a set of offset Offenhauser adapters for the carbs to clear each other end for end, unless they are mounted reversed from each other, with complicated linkages, and sideways on the intake manifold, there just isn't room for them to clear each fuel bowl. The only Holley carbs that will actually easily bolt end to end, to the stock and aftermarket inline 2x4 Buick stuff is the 450 cfm spread bore Q-jet replacement carbs, but then, they would need a spacer plate to allow the secs plates to clear the manifold bore hole sides.
Thank you Tim and Dave. I wasn't quite sure what type of Holleys he has. Dave, your answers are always so excellent. :TU:
I kinda figure two of the universal 450 cfm spread bore replacement type Holley's would work exellent on a 2x4 NailMotor. Run both open, not progressive, use an adapter for each to match the carb bores to the intake, and it shbould be a good deal. I used one of these carbs on my 215 engine years ago, was the second best carb I ever had on it, just a tad behind a good used 1850-3 600 cfm Holley carb. 900 cfm on a NailGun ought to be just about right, and they bolt to the Carter narrow stud pattern. Just a thought.
Do these dual carb manifolds you guys are talking about use a common plenum (both carbs feed all cylinders)? I was under the impression on the 400-430-455 offy dual manifolds that each carb feeds 4 cylinders. Too bad they wouldn't have done it like the manifolds being discussed here, as much as those motors like to breathe.
Hi Steve, Yes, these are open. They use the rear carb(with choke) for regular driving, and have a linkage to open the front; first two, then all four barrels, depending on how far you mash it to the floor. I found the best way to launch during street races(a long time ago) was to slowly but steadily push the gas to the floor in each gear to keep the engine from bogging. Dan
thanks form the advice with the launchingwhat about with an auto? should i step on the gass slowly then stomp it or just open it up off the line or what just curious hope its not a stupid question
