2x4 carbs "428"

[car-zone]

1968 Ford 428 Police Interceptor block
Sealed Power .030 forged pistons (yields 10.5 to 1)
Factory 13/32" rods
Stock crank
ARP fasteners
PI heads with CJ stainless steel valves, ports mathced to intake and headers
Police Interceptor intake
750 cfm Holley with Proform main body
MSD 6AL, Petronix electronic ignition and coil
.562 with .302 duration hydraulic lifters
Sealed Power valve train, hd oil pump, timing set, rings, etc
Edelbrock water pump
Carter fuel pump
Sealed Power roller rcokers with HD shafts and supports
Autolite 45 plugs

[lovehamr]

Since this thread is re-opened I do have a question about lateral Gs with side pivot float bowls. For years I've driven and raced Boss 302s, at one time I found an original Shelby 2x4 intake for it and ran it with 1850s for a while. In a staight line it went like stink but on a road or auto-X it would stumble all over the place in the corners. After setting the float levels to 10 or 20 different levels I gave up and went back to a 780 with center pivot float bowls and the ability to go around corners was returned. So my question is; how do you guys who run your cars get around the lateral G thing with multiple carbs?

Steve

[Excaliber]

Side pivot float, not good for a road course, or even street use under heavy braking/cornering. That's why the Comp cars ran the center pivot single four which are to long to run in a dual configuration.

How do you deal with it? Set the float on the low side, heel/toe the brake/throttle when you need to, try to keep it from stalling if you screwed up the heel/toe, avoid cone racing. Learn to deal with it...

At the end of the straight coming down from about 130 mph into a hair pin corner was the biggest challenge on the road course here. I had to really pay attention with the braking, gear selection, getting back on the throttle "just right" or it would flood big time! It actually did OK in the other corners because your back on the throttle quick enough.

I'm running twin 600 Holleys vacuum secondary, they work OK. This is the THIRD set of carbs I've had on it, every set had the same problem under hard braking/cornering, fuel slosh. IF I was going to do some serious tracking I'd go with a center pivot. But I'm mostly street and the dual fours look cool, so I live with it.

[undy]

I get the hard brake/lateral G bog on my QuickFuel 750s too. Are their any "in the bowl" bandaides to help take care of this, slosh tube or sumpin??

C'mon BarryR, 12 years at Holley had to give you some insight on this one..

[lovehamr]

So this means that anyone running two 4s can't brake and get around a corner in an expeditious fashion(equal to a single 4 with center floats)? Or is everyone holding some cosmic secret back? If not, as cool as two 4s looks, I guess I’ll be sticking with a single 4.

Steve

[patrickt]

Originally Posted by lovehamr

So this means that anyone running two 4s can't brake and get around a corner in an expeditious fashion(equal to a single 4 with center floats)? Or is everyone holding some cosmic secret back? If not, as cool as two 4s looks, I guess I’ll be sticking with a single 4.

Those of us with simple, center hung Holleys do not complain about a drop-off while breaking or cornering. Most of the guys that go with a 2x4 do it for the looks, although I recall Barry R. reporting that there is indeed a slight advantage on the dyno for a 2x4 setup over that of the single four barrel. I do not know of anyone that experienced the drop-off problem and then remedied it by making mods to the 2x4 setup. Either they don't experience the problem (perhaps they just don't drive that hard) or they switch to single four or even FI, Webers, etc.

[Cobra #3170]

Originally Posted by lovehamr

Since this thread is re-opened I do have a question about lateral Gs with side pivot float bowls. For years I've driven and raced Boss 302s, at one time I found an original Shelby 2x4 intake for it and ran it with 1850s for a while. In a staight line it went like stink but on a road or auto-X it would stumble all over the place in the corners. After setting the float levels to 10 or 20 different levels I gave up and went back to a 780 with center pivot float bowls and the ability to go around corners was returned. So my question is; how do you guys who run your cars get around the lateral G thing with multiple carbs?

Steve

Back in the late 60's I had a tunnel port in my Cobra with the single plane dual four manifold, I made adapter plates and turned the center pivot carbs 90 degrees like some TranAm cars and used dual cables to work the linkage, that worked pretty well but I don't think anybody on CC would like the "look".
I finally tried dual 550 cfm Holley two barrels with adapters on the dual four manifold that actually seemed to work the best in terms of flooding/starvation and made decent power. Thank God for fuel injection though, I have never had a carb set up that did not have a stumble under heavy braking and or cornering including Webers on a formula car.

[Barry_R]

Sorry it took so long to catch back up on this. The side pivot floats are at a disadvantage in handling turning loads - but they should be more than good in acceleration and stopping.

Oval track guys do sme interesting float modifications - angled cuts and then resealing with epoxy on nitrophyl floats. I do not know what impact that would have in a road race environment but it would be inexpensive to experiment. Some of the angled floats are available commercially for the center pivot carbs - but nothing I am aware of for side pivots.

[Excaliber]

Some years ago I read an article in a 4X4 magazine that was about the modifications you could do to your 4 barrel carb (Holley in particular). The concern was fuel slosh and stalling at the extreme angles encountered during serious off roading. Seems to me float modification was a key component, along with a tube on the bowl vent(s). There were several other tips and tricks that I can't recall. The problem was never serious enough for me to warrant doing anything more than making sure my float level was slightly low.

[tmareina]

I run 2 660 Mechanical Hollies on a Dove Tunnel Wedge. My 428 was dynoed at 614 HP. Great throttle response no issues or adjusting in the 2 years I have driven it since the rebuild in 2007. Tom Lucas at FE Specialties did a great job.

Tom

[saltshaker]

looking to get the carbs adjusted correctly...any suggestions. the exhaust really smells at idle of fuel.
Jon

[Argess]

Saltshaker...check out this thread and note my post with pic on idle problems with twin 4-barrels. May be of help:

Which carbs do I want for 2x4 MR?

Here's the fuel slosh mod....check out figures 5 and 6 on pages 6 and 7:

http://www.holley.com/data/Products/...99R10268-4.pdf

And heres a site on doing the mod yourself:

http://classicbroncos.com/tech/offro...4-barrel-carbs

I have to try the slosh mod myself....I seem to have idle issues after hard braking and hard acceleration.