Kicking around the idea of switching my Merc's 322 from the stock WCFB/intake to a pair of Carter dual fours on an Offenhauser intake, mostly for the "cool" factor. The engine runs great right now, and gets about 19 mpg (has a 700R4 trans), so I'm a little leery about ****canning what's there, but it just doesn't "wow" like the rest of the engine compartment. Was wondering if anyone has done the swap on the old Gen 1 Nailhead, and if the little guy can actually use that much fuel? According to the nailheadbuick.com guys, the Offenhauser intake is inherently more or less "terrible" and needs correcting to distribute air/fuel properly, some cylinders run super lean and others super rich, has anyone had any experience with that? There's a couple complete intake/carb combos on eBay currently for under a grand, but don't want to blow the money if it's not a good combo for the otherwise stock 322. There's also a an Edmunds and an Eelco intake out there, but they're quite a bit more money before even getting into the carbs, so I'd like to stay with the Offy unless anyone has any real "don't touch that piece of ****" advice, at which point I'll save up for one of the others. Any help/experience/advice is appreciated.
I have not done back to back dyno runs comparing the Offy to the stock nailhead intake. However, have built a number of setups for customers that did not want to spend O.E. bucks, and no one ever complained about the performance. In fact, more than one customer mentioned that the setup I did ran BETTER on the street than the O.E. setup. Decades ago, we settled on using Offy manifolds for aftermarket; BECAUSE THEY ALWAYS FIT !!! AS with any change, there is always engineering involved. Yes, you could probably bolt on a dual quad intake and two 750 Holleys, and the engine would run, and maybe pretty well at wide open throttle. But selecting carburetors based on the engine, m*** of the vehicle, how it will be run, etc. will give more enjoyment in the final product. As an example, on a 400 CID nailhead, we found the best running setup on the street using the O.E. intake, was replacing the originals with a pair of 400 CFM Carters running straight linkage (the originals were approximately 650 each, running progressive linkage). As to the comment about some cylinders running lean, others running rich, I would ask: How good is "good enough"? When we replaced the originals with the two 400's on the nailhead mentioned above, all we changed in the carbs were the metering rods; and the customer was delighted in how much better it ran than with the O.E. units. But, there was room for improvement, we just didn't need to go there. Take a look at the FACTORY calibrations on the late dual quad hemi carbs. Dual quads, so there are 4 metering rods (yes, I speak in Carterese), and 8 jets. On one setup, the factory used 4 different rods, and 6 different jets to compensate for the pulsing of the various cylinders. And that with the factory intake. How good is "good enough" ? If you want the look of dual quads; GO FOR IT. Do your homework, and you will be pleased with the change. Jon
I read on a Buick site a few years back when I was going to run an Offy 3-2 manifold on a Y-Block that because of the crazy p***ages on ALL the Offys that using a hole saw drilling thru all 8 carb holes to open all the p***age made the manifold perform as good as all the rest. I know the Offy 3-2 Ford was a POS when compared to others of the era. ……. Just a thought.
Go to nailheadbuick.com and look under Matt’s tech info. They explain what’s wrong with the Offy intakes and what they do to fix them. Could be DIY mods if you have the equipment. I would run one on a cruiser with or without the fix but I wouldn’t count on it giving maximum power. I agree with you, they look *****in, especially on an old nailhead.
Thanks for the info and help everyone, I appreciate it. Found out one of my trucks is going to be on Bring a Trailer, so after that I think I'll bite the bullet.
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