Hey guys. I'm almost done with my '66 401 Nailhead and I currently have the original single 4 bbl as well as an Offy 2x4 setup. I hear the offy does not flow well and I would actually lose 50 horsepower. That seems like an awful lot to lose! Is this accurate? If so, I'd love to get some input from you guys about other intakes like a 6x2. I know they would be much smaller carbs (either Holley 94s or Stromberg 97s) but I wanted to see if anyone runs these and how you like it. Also, anyone have experience with the Speedway versions of the 97s? They are called 9super7s and one of my friends bought one and hates it although it gets great reviews online.
Yup. Thats where I get my parts and info from. I was just looking for some opinions from guys here who run nailheads. I wanna hear the good and the bad
Back in high-school my auto shop teacher had a '65 Riviera...w/Factory dual AFB's. I can't believe they would have less H.P. than a single carb. Maybe not a bunch more....but I sincerely doubt any loss.
No, not saying 2 carbs would have less Hp. Its the brand of intake that seems to be the issue. I heard the stock 2x4 manifold is good, as are the Edelbrock and Weiand, but my Offenhauser has terrible flow.
search online, I have seen a flow comparison chart but can't find the link.....I think it was when eelco was developing their manifolds..... what are you putting your 401 in?
Zombie 51,I am running a offy 3x2 intake with 2g rochesters I got from vintage speed for my 401 and that think pulls like freight train...but I would trade it for b262 edelbrock intake with 2 500cfm edelbrock carbs if I could find one ,just because I had one back in the day...GOOD LUCK...
I'm curious about this too. I have an Offy dual quad setup on my 401 and it runs OK, wondering what it would do against a 4x2 or 6x2 setup, or even a supercharger with my dual 4bbls... -Dean
Yeah that Edelbrock b262 seems to be the one to get but I haven't seen them around. I've spotted a few stock Buick ones though. Russ Martin tells me the 6x2 works really well and greatly improves gas mileage as a bonus
years ago, when i was a kid, i had an uncle that was a nail head fanatic, he put them in everything. He left me a lot of stuff when he passed. I got to ride in everything he hot rodded, and i remeber talking about this and that, and the absolute best performing set up was a Qjet intake with a 1000cfm thermoquad, it just worked...Carmen Fasco told me the exact same thing, hes a nailhead guru... the best dual quad is the edelbrock then the factory intake and the offy is a horrible performer.... he had i believe a dragstar 6x2 or maybe a simular one and hated it, nothing but problems...kinda the old saying keep it simple..
When I was doing research on the 425 (when I had one years ago) I came up with. Best to worst 1. Stock 2x4 intake 2. Edelbrock 2x4 intake 3. Stock single 4bbl with the quadrajet ('65 only ???) 4. Stock single 4bbl with the carter 5. Offy Not sure on the 6bbl logs though. Sadly I HAD the stock 2x4 and the single quadrajet.
I don't have a lot of opinions yet but probably will by this summer, here's my 50 merc with a 425 nailhead, eelco manifold and a pair of 500 cfm thunder series carbs.
I have a Q-jet intake on the 401 in my company car with an Edelbrock Q jet sitting on top of it. It looks like I have an adapter under the carb but it's a spacer I made out of a 3/4" chunk of aluminum. The linkage on the carb hit the manifold so I had to raise it up and mill out some of the spacer to clear the linkage. Apparently the factory Q-jet had a different set up on the linkage. I had a factory 2-4 set up in the car for a while and I hazzard to say that the Q-jet will keep up with it and get better gas mileage in the process.
They are (but I haven't looked for a few years), I cleared about $1700 on ebay for the 2x4 with carbs (no linkage or air cleaner), the quad intake and carb and the stock buick aluminum valve covers in the early 2000's.
The two best 2x4 intakes are the Edelbrock B262 and the stock 2x4 setup so I am told. There is only a marginal performance gain going from what you have to a 2x4 setup unless you have some work done to the motor. Talk to Gessler Head Porting, there is none better out there!! They will provide excellent advice and guidance. http://www.gesslerheadporting.com/ I have the Edelbrock B262, I hear they are getting rare and hard to find so if you see one, pounce on it!! They look great too! As you can see. Thank you for the guidance there Oldtimer, I did not realise they were quite that much these days! Doc. (Been doing a lot of research!)
So would I. Don't have anything to contribute right now except interest. Have you seen this thread at the V8 forum? http://www.v8buick.com/showthread.php?225437-Doc-s-dual-plane-mod-and-port-matching-stky Supposed to offer up some ponies.
401 in Mdl a, stock cast iron 4 bbl manifold with Edelbrock 750cfm, user friendly combo. Check out the Russ Martin website; he's the Nailhead guru.
I would definitely not run an offy intake unless you have Russ modify it. I had 1 before and swapped back out for the factory 4bbl. I have had the factory dual quad intake w/carbs and that ran great all above was on a stock 425. Right now I just picked up a NOS weiand drag star for my 322. Hopefully by spring I will have that up and running.
Have a look here https://www.teambuick.com/community/index.php?forums/fuel-systems-intake-to-exhaust.160/
John the Carter AFB guy is selling Thermo Quads.. http://www.thecarburetorshop.com/Triple1barrels.htm They are a very nice carb. Make sure you remove the bottom screw when taking it apart!! I would try to get a Quadrajet intake with the Thermo-Quad or maybe get the grinder out on a stock square bore 4bbl intake and try to blend it into a spread bore.. For a street ride, a single 4bbl is hard to beat, especially a Quadrajet or Thermo-Quad... Good luck..
Have never done an Offy/Edelbrock dual quad comparison on Buick, but have on Pontiac. While not quite as good as the factory Pontiac dual quads, the Offy blows the Edelbrock away, by a bunch. Interesting that the results would be totally opposite for Buick and Pontiac. I have an Offy on my shop truck, and very pleased with it; and I have an Offy for my GTO, but not good enough with sheet metal to match it to the shaker. It will probably stay in the box. Again, have never tried one on a Buick; but the factory dual quads run like a scalded dog! Elco - thanks for the plug Jon.
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