Does anyone know if the WCFB carbs used on the 56 Corvettes had the same small base as those used on the Mercury in 1957?  I see a lot of WCFB dual quads on e-bay for 56 and 57 Chevy and very few for Y-blocks.  Was the carb used on the Chevy essentially the same as on the Y-block?

Mike K

Yep, base size is same. Merc WCFB's were vacuum secondaries while Vette's were weighted arm (mechanical). Scrub might be cheaper in the long run as '57 Merc Turnpike Cruiser WCFB was a one-year only deal.

BrodieSavannah, GA

WCFB's were also used on a variety of other GM products, including Pontiacs, Cadillacs and Oldsmobile. I don't know what form of secondary activation was used but there are other choices for carbs.

Frank/Rebop

Bristol, In ( by Elkhart) 

Rochester 4GC series carbs from GM cars of the '50s also have the same bolt pattern, although I've heard they are too large to be placed in tandem on a Ford dual 4 manifold.  Single 4 would be OK. 

John - "The Hoosier Hurricane"

I put a pair of '56 Buick 4GC Rocherter carbs on a '57 Ford 2/4 manifold after seeing it done on a very quick '54 with a 312.  He did it by putting about 3 1/2" spacers under the rear carb.  This allowed part of the float housing and fuel port of the front carb to fit under the rear carb.  They were relatively large venturi carbs with the small sq bolt pattern but they were a bit longer than the Carter WCFBs so that may be why GM didn't use their in house carb for 2/4's

I did it by turning the front carb backwards then fabricated offset studs and spacers to separate the carbs enough so they could both sit at the same level in the manifold.  I also had to turn the secondary throttles around in the front carb.  The Linkage was double progressive, 2 then 4 then 8 barrels, Most normal(?) driving was done on the primary barrels of the rear carb. This worked surprisingly well and was by no means the worst part of the whole setup. One bad part of that setup was the close ratio top loader and the auto trans rear axle.  But 22 miles to the gal at highway speeds was the norm with that combo.  This was circa 1966 and unfortunately I do not even have a picture of the carbs or engine anymore.

My memory of the Rochester carbs is pretty dim but I think they were almost as simple as the 4100 Ford/Autolite carb.

Doug T

The Highlands, Louisville, Ky.

I know that when the WCFB was used as a dual quad setup on the Ford and Merc it had weighted arm secondaries, but it also had an idle circuit that was not in the carbs used for single 4-bll applications.  The single 4-bll applications had vacuum secondaries and I have several of those, but none with the weighted arms. 

I have seen only one set of WCFB dual quads with weighted arms on the internet in about four years and was outbid for what looked in the pictures to be fairly rough carbs.  On the other hand, a lot of WCFB dual quads for 50s Chevys have been advertised.  I wondered if the Chevy carbs would bolt on a Ford E-code manifold.

I also note quite a few "dual quad" setups advertised that have vacuum secondaries.  I don't know if those are simply carbs for single 4-bll applications someone bolted on a 2x4 manifold or if they were the real deal.

Mike K

Frank,

I was specifically curious if the Chevy dual quad WCFB carbs from 56 or 57 might be a substitute for the Merc WCFB dual quad setup which had mechanical secondaries with weighted arms and a special idle circuit for dual quad applications.  I have a number of WCFB carbs from single 4-bll setups, but they all have vacuum secondaries.  I just wondered if the Chevy dual quads were essentially the same as those for Fords of the same period.  My only dual quads on E-code manifolds are Holley tea pots and I was wondering if the WCFB might be a better setup.  I don't know anything about the Chevy stuff.

Mike K

Mike,

  The reason I brought that up is because those carbs would be a lot cheaper than "numbers matching" dual quad Chevy carbs. I'd think the vacuum secondary carbs, after you figure out how much spring to use, Might work pretty well. Doug seemed to have had pretty good luck with the 4GC's which are also vacuum.

      As far as the carbs being the same between the Merc and the Chevy, I'd be amazed if they were. The base mounting will be the same though.

Frank/Rebop

Bristol, In ( by Elkhart) 

Mike,

I wouldn't recommend any 60 year old carbs anymore but if you want to find out as much as possible about the WCFB's as used on Mercs I would suggest that you contact The Carburetor Doctor http://www.carburetor.ca/.  He has seen a lot of carbs and may know what the differences are between the FoMoCo and GM applications.  You can also google Carter WCFB and come up with at service manual to look over.

BTW I think that the '56 and 57 2/4 manifolds differ as they came from Ford.  The '56's had more space between the carbs.

Doug T

The Highlands, Louisville, Ky.

All,

Thanks for the input.  This gives me some leads to follow up.  I am not sure where I might head with this, but did want to learn more about it.  Originally, this started when I got out bid on a set of original Merc WCFBs with the manual secondaries and idle circuit.  Since then I have kind of watched WCFBs on E-Bay and never saw another set, but lots of WCFBs, including Mercs.  One e-code 2x4 manifold I bought had some WCFBs with vacuum secondaries bolted on it.  They were basically scrap iron, but I wanted the manifold at the time and only later learned the distinction between the single 4-barrel and dual quad carbs.  I guess I just got curious.  I will get the WCFB service manual and check it out - good idea.

When I bid on the actual dual quad setup, I was thinking along the lines of original restoration.  Chevy carbs probably don't fall in that category unless they are exactly the same as Mercs or Fords which is unlikely.  However, this got me wondering about the other WCFB carbs.

Again, thanks for all the input. 

Mike K