So I have a 272 built up with 30 over pistons and a mild cam grind. The intake manifold that I have is a Ford dual quad aluminum. Original 57. Question is, should I bother rebuilding my Teapots ( they need to be modified to run a later model dizzy ) or do I run a more modern set up? What CFM do I go with? What make of carb are you guys running on your dual quads?

Johnny you will get lots of opinions and some good advice on this. Personally I might go looking for a pair of the old 400 cfm Carter AFB carbs, but that's just my opinion. Anyway here's a bump for the evening crew. -Dave.

Even with a .030" overbore a 272 will not exceed 280"s  With what you describe as a mild cam (?) I guess it's possible to tune dual 4s for that, but I doubt it's worth the trouble. A decent size 4 barrel will likely give you about all the carb that engine can use..     


Paul

While the performance is roughly about 20HP more with a modern aluminum intake and carburetor, the WOW factor for the dual quads makes any potential loss of power worth it.  For the dual quads, the advantage to using the Teapots would be the vacuum secondary operation along with the smaller cfm ratings associated with those carbs.  When properly tuned, the vacuum secondaries will only open the amount that the engine requires so it would be difficult to over-carb a smaller cubed engine with a pair of these.  The predecessor to the Holley model 4000 would be the Holley model 2140 that came on the ’53 & ’54 Lincoln and Mercury engines.  The model 2140 4V carb has some similarities to the ’55 and ’56 model 4000 Teapots but the big difference being that they are smaller in cfm ratings due to the choke being located within the primary venturies.  I’ve found that the carbs off of the Merc 256 engines (List #806) to be excellent performers on Y’s with dual quad setups.  Here are pictures of a pair on the 312 dyno mule.
    
This particular pair has been modified to work with the ’57 and up distributors and also incorporates the equalizing vacuum transfer hose between the carbs so that the secondaries open simultaneously.

As has been brought up before in other threads, the early Cadillac, Buick, and Oldsmobile Carter and Rochester carbs also bolt directly to the early Y dual quad intakes and can be made to run well.  Most of these do have mechanical secondaries so you’d have to watch out for some bog or hesitation if the throttle was opened up prematurely either due to gearing or rpms.

The problem now though is simply finding a pair of matching older carbs.  Modern carb options would require adapters but in that vain of thought the Edelbrock 500 cfm carbs, and the Holley 390, 450, and 465 carbs can be made to work in dual quad configuration.  The Holleys would have to be mounted sideways on most dual quad intakes except the Edelbrock FM255.  On the FM255 intake and with standard adapters, the Holley carbs can be mounted in an inline fashion.  Looks like this:
 

Lorena, Texas (South of Waco)

Johnny.. I use small base Carter WCFB's similar to the ones on some 56 Mercs. If you set them up progressive like I did you only run on the rear one unless your on it. My set up is on a stock 292 and there many photos on the site if you do a search. I'll send others of what I did for all the linkage, fuel, choke and vacuum lines if you like.
After a little teething I'm really glad I did it. Good Luck.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

Thanks drylakeracer. That's exactly the info I'm looking for. Pictures would be great.

Hey guys. I'm still looking for some guidence and tech info on what are the best carbs to use on a dual quad manifold and how to set them up. What are some of you using. Thanks in advance.

Johnny J;
My 292 motor is bored 0.060" over with a 312 crank and 292 (C2AE) rods which required the pistons to be milled about ).062" if I remember right. I'm running a Comp Cam with a .489 lift and an Edlebrock #257 manifold with dual Edlebrock #1404 (mechanical choke) 500 cfm carbs. I did use "Trans-Dapt" carb spacers, but that worked out well The motor was dyno-tuned in Boise Idaho and it does run very well with the progressive linkage

  Ron Lane,  Meridian, ID

JohnnyJ..sent you a PM on what I did. You can go to this Techincal heading on this site and see many of my photos
 1956 Y-Block Dual Quads I can send many more if you like. E-Mail me at gmc6power@earthlink.net  and I can do close-ups of any area and what I did. You will see in the listed photos I use very close to stock linkage and  Ford-o-matic  trans linkage..once again good luck

56 Vic, B'Ville 200 MPH Club Member, So Cal.

Thanks again.