Ok, so I’ll start by predicating that I’ve poured through threads for the answer already and read through tech to no avail. I have a late 371/394 Offy dual quad intake that I need to have cut to fit the lower deck height 324. (I know I will need to do port work on the heads for flow). I have found that the early 371 intakes need to be cut between .100 and .125 to fit 324’s, but no hard numbers on the next group of intakes for the taller decked later 371/394’s. Question: does anyone know or have the amount that needs to be machined off the ‘60-up Olds intakes to line up(mounting holes) on a 324? Sent from my iPhone using The H.A.M.B. mobile app
I really think that there is too much port size difference to be able to do this, I think by the time you machined that much material off to get the width correct there woulden't be any flange left. Maybe someone else will jump in here on this.
Some pics may help I suppose. The outer flange appears plenty thick. Idk about the lower area. Hopefully I can get some clarity here. Sent from my iPhone using The H.A.M.B. mobile app
The holes are about 2/3 covered (intake stud/bolt holes are significantly larger in diameter than threaded holes in the heads) Sent from my iPhone using The H.A.M.B. mobile app
Why not just start milling a little off of each side and sneak up on the fit. When it fits post the total to save the next guy all the research.
I have an Offy dual quad manifold for an early Olds that I will probably not be using. I could probably be convinced to part with it. It is on a '51 engine I bought to restore my race car and I have the Offy three deuce manifold that was originally run on this particular car that I am planning on using. PM me if interested. Why cut up a good manifold, especially if you can't be sure it will even work?
I don’t have access to a mill in order to do that. After looking at the runners I think the above comment is true.. there’s not enough meat in the bottom for it to work. Sent from my iPhone using The H.A.M.B. mobile app
Hey Tubman, is it the super open plenum type where it has no exhaust crossover (just a thin blade of aluminum and a pad that covers the exhaust crossover port)??? Sent from my iPhone using The H.A.M.B. mobile app
looking at the bolt lineup, you would be better off making adapter plates. fwiw, welcome to my club, for my buick 350, i cut up sbc's, 455 buick, sb mopars to make my different intakes.
I vaguely remember someone commenting on this very issue in the past saying that there isn't enough meat on the flange to mill it down to fit, so what you're trying to do may well be an impossibility with the intake you have.
Sell your 371 and buy the right one. I paid 500 for a perfect Y-Block dual quad 6 years ago. Old's 303-324 are out there you don't need a headache. Adapters to later carb are available too and some I've seen come with them. Good luck, you'll never be sorry.
I saw that, and was hopeful. Sadly it too would need to be machined. If you blow up the pic it’s stamped “57 58” just below the “O4D”. Those earlier Weiand intakes had years stamped on them, and the later ones had letter codes stamped next to the thermostat housing. A = 49-55, AB = 56 (A denoting 303/324 deck, B denoting larger ports for the 56 heads), B = 57-58, C = 59-64. I am scraping the idea and am gonna resell this Offy intake. I have found a couple of the 60’s style Weiand WO4D intakes that will work as well as an Edmunds 2x4. It’s just a matter of deciding which will better suit the style of my build (think Chrisman’s 29 sedan), as well as which will perform better. Anyone have experience with the Edmunds 2x4’s and can speak to performance? Thanks for the responses everyone! Sent from my iPhone using The H.A.M.B. mobile app
Those manifolds deffinately do not interchange like that. Weiand used the same casting number but machined them to fit different years. Weiand stamped them A, B,or C in the front of the manifold to designate the years they would fit.
Yup I noted that above. The early variant like that noted in that eBay ad above (O4D) actually carried numbers denoting fitment. The later WO4D intakes carried the alphabetic designation. But... There’s actually an AB intake as well in those later intakes that had the lower deck fitment but larger intake ports (I’m assuming for 56’s or earlier motors with later heads) like the two below. Also, I already contacted the seller of that one and they have since corrected the listing (they also had a later one listed similarly that was a C code). Sent from my iPhone using The H.A.M.B. mobile app
OK. I snuck up and got a few pictures. Unfortunately, the engine is tucked way under the stairs and hard to get to. I also took a flashlight and stuck my head in there and took a good look at it. It is an Offenhauser, but I could find no markings on it other than the word "Offenhauser" in two places (between the carbs and across the front). This, and the fact that it is on a '51 block with unmarked heads, leads me to believe that it is for the smaller port '49-'53 303 heads. I could be wrong on this, though. One more thing; after looking this over good, I have to believe that this manifold was new when it was installed on this engine many years ago. It also has "square bore" (WCFB, early 4G) mounting pads and will need adapters to run later carbs (just about every early Olds manifold seems to be for the older carburetors). Sorry about the quality of the pictures; it's been under the stairs for at least 15 years.
Thanks to everyone that chimed in, offered advice, and offered up their own parts. Problem solved over here on my end. Got an AB coded Weiand intake in near perfect condition and will compliment the early 60’s style I’m shooting for. To those who may be concerned... I replaced those mismatched gaskets with AFB gaskets to ready it for a pair of AFB’s or Edelbrocks. Sent from my iPhone using The H.A.M.B. mobile app
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