WCFB 2 X 4 question

[Mark P.]

I am about to install a set of restored WCFBs on my 245HP rebuilt engine.

Is there a risk of fuel flowing into the cylinders and causing a hydraulic lock-up that would damage my engine ?

[John H.]

Re: WCFB 2 X 4 question

Is there a risk of fuel flowing into the cylinders and causing a hydraulic lock-up that would damage my engine ?

Nope, unless the main body and baseplate castings are cracked.

[Mark P.]

Re: WCFB 2 X 4 question

John,

Thanks for clarifying. Someone mentioned to me that if I park my car with the rear section higher than the front there is a risk that fuel could leak into the cylinders with dual WCFB's. They said this also could impact the mid 70's Holley tri powers and Fuelies in general.

The anti-siphon valve fixes the Fuelie issue, right ?

Mark

[Ian G.]

Re: WCFB 2 X 4 question

My understanding is the issue happens with fuelies, not due to a cracked baseplate or orientation of the car, but from fuel siphoning out of the spider and into the cylinder... I have an original anti-siphon valve and two of the newer ones. I'll probably put it all on to be safe

[Mark P.]

Re: WCFB 2 X 4 question

Ian - John was addressing this issue for WCFB's, not fuel injection units.

Mark

[Ian G.]

Re: WCFB 2 X 4 question

I know. didn't mean to imply tha he was wrong regarding fuelies. just mentioning what causes it for fuelies...

[Stuart F.]

Re: WCFB 2 X 4 question

Mark;

Just make darn sure your fuel connections are clean down stream of the filter. My experience in the past has been that WCFB's hang up their floats easier than other carb models, but it usually occurs during start up due to debris. If you are confident your carbs were well built, floats set up and aligned right, needle/seats properly installed, fuel lines clean and clear, you should be OK. I used to build up multiple carb sets for drag racers and had a few hang up due to the owner doing a sloppy installation, and that is why later I insisted on doing the install myself. We had one 56 E-Gasser at Great Lakes Dragway spewing out flame from his hugh boxed headers on his first start up at night, and of course he blamed me shouting; "Do Something!" "Do Something!" So, I jumped up on his elevated front end with my hefty screw driver and gave each carb a good rap! and all was well with the world. He went on to set a record that night and impressed the crowd as well.

Stu Fox

[Mark P.]

Re: WCFB 2 X 4 question

Stu - thanks for your response. The carbs were just restored by Chuck smith and am installing a new fuel filter and line kit from Paragon. Should be OK then.

Do the dual WCFB's have noticeable performance versus the base 230 HP single WCFB ?

Thanks,

Mark

[Richard M.]

Re: WCFB 2 X 4 question

Stu - thanks for your response. The carbs were just restored by Chuck smith and am installing a new fuel filter and line kit from Paragon. Should be OK then.

Do the dual WCFB's have noticeable performance versus the base 230 HP single WCFB ?

Thanks,

Mark

Well, I guess they must because they are rated at higher horsepower, and........

I certainly like the sound of my 8 barrels when I get "on it".

They look pretty cool standing still too! Just wish they had throttle shaft seals though. Be cautious about leaks.

Rich

[Stuart F.]

Re: WCFB 2 X 4 question

Mark;

Theoretically, you should see about 15 hp improvement (Duh!) of course, but so much depends on whether your engine is set up to use the extra carburetion. Mostly, on the lower HP (lower Compression & milder cam) engines, the dual quads provide low end excitement more than anything - what with the three stage progressive throttle. This is specially appreciated with the low restriction Corvette air cleaners when accelerating under an overpass or in a tunnel where you can get the full sound effects. For racing, we used to set them up to run both primaries together for more low end torque (if needed/wanted), but on the street your mileage suffers a lot. On the higher performance engines (w/compression and cam), the dual quads run out of breath at higher RPM's, say compared to a fuelie. The models used on early Vettes aren't all that big CFM wise. I used to replace them (again for racing) with carbs from a Caddy El Dorado mounted on adapter plates. They had 1-1/8" venturis in all four bores, they ran both primaries together and used air idle screws. I would sneak them on for top stock eliminator or top speed runs, and definitely for Sunday night $50. street runs against the commandoes that wouldn't come out to the strip.

Stu Fox

[Tom P.]

Re: WCFB 2 X 4 question

The WCFBs on a factory 2x4 setup flow ABOUT 385cfm each, for a total of about 770cfm.
That's more than a lot of the larger Holleys!!!
Thus, theoretically, a 2x4 setup would work very well on a 350 or 400 engine. And when properly setup, they work GREAT on bigger displacement engines. The drawback is the somewhat restrictive intake system compared to some of the later, better designed hi-rise manifolds for a Holley.
In past years, I have run the WCFB 2x4 setup on a SB400, and the low/mid-range was incredible!

[Steven B.]

Re: WCFB 2 X 4 question

Mark, I would not worry about Chuck Smith's rebuilds. If you want to have some fun with acceleration first set up the linkage so the front four barrel comes in as factory set at a higher RPM. It works real well for 100 MPH stomp downs. Then , adjust the linkage so the front carb comes in sooner (there are two holes on the linkage - a front and back). Take it out, and dump the clutch at 3000 and hold on. Make certain the pavement is wide and be certain to recycle the rubber!

Let us know how it performs with the dual WCFB's!

Steve

[Mark P.]

Re: WCFB 2 X 4 question

Thanks everyone. Feeling better about the path I went down.

[Stuart F.]

Re: WCFB 2 X 4 question

Mark;

One of the limitations of the factory dual quad manifold that Tom was eluding to is, of course, it's flow characteristics. One improvement we made back in the day, unfortunately, is not available to Corvette applications.

I was horsing around one day when I had the headers of my 57 post Bel Air and ran the engine w/o them just to see and hear what it was like. In the process I noticed that cylinders #2 and #8 were showing a more yellow flame than the others and deduced that they were, in fact, running leaner. Then when I tried to figure out why, I noticed or recalled the manifold uses cross cuts in the base flanges to those two cylinders. well, obviously, there was little I could do to modify the design to overcome that deficiency (more than the factory already did) without doing something to pack up more manifold area before those two cylinders, and the only way to do that was to put spacers under the carbs. I had a bunch of 1/4" fiber type spacers which I took and added the cross cuts to. Through trial and error, I determined I needed to raise the carbs 1-1/4" each, and that changed the color of the exhaust so they were all equal. On the chassis dyno, I picked up about 18 hp doing that. But that extra heigth is not available to Corvettes, unfortunately due to the low hood clearance.

[Tom P.]

Re: WCFB 2 X 4 question

But that extra heigth is not available to Corvettes, unfortunately due to the low hood clearance.

It is if you cut a big hole in the hood and Pop rivet a big scoop on it!