Thank you Guys for the wonderful responses.

I was aware of the vacuum line balance tube and the secondary springs, but not the power valves, so that's very helpful.

I'll be using "regular carbs", either the 55 type or the 56, just depends. I've got a matched (list numbers) set of the 56 type. These carbs are going on a 288 CI Ford Flathead V8. The reason for the carb type is that it fits the period that I want, and I can kinda hide the carbs under  older type air cleaners. The carbs will be linked directly, and with the vacuum only secondarys, I think will work just fine.

I'm going to send an email to the Randy guy and see if he can add anything to the already great responses from all of you.

Thanks again

Jim

Jim:

Years ago I raced my 230 horse '56 Bird in NHRA stock.  Some things I tried that did not work.  Putting a screw in the secondary throttle slots to make them mechanical instead of vacuum.  Larger or smaller jets.  Substituting non-dual carbs for the dual ones to try to get more airflow with the less restrictive boost venturi.  Boring the secondary throttle bores oversize (not legal, but at least I didn't bore the original '56 dual carbs).  Playing with power valve springs.  In a nutshell, I found that the factory setup was the best I could do.  Mine was a '56 setup, which was an over the counter racing kit, so may have been optimized by the factory or a Holman-Moody type shop.  I did convert to a fully mechanical distributor.  I found that 6 psi fuel pressure was adequate and did not cause flooding.

I remembered an article in Y Block Magazine about dual carb tuning, so I looked it up, Issue 72, article by Dan Del Duca, '57 E Bird and a pickup with 2-4s.  He said he opened the manifold under the carbs to make open plenums, which he thought would reduce low rpm torque, but it seems better.  Undocumented opinion.  His carb tuning amounted togetting them rebuilt and recalibrated by his "carb guy".  No information about him or his modifications other than enlarge some fuel passages because they were so long.

John - "The Hoosier Hurricane"

If you don’t already have the List 1434 and/or 1437 Holley carbs, then pay particular attention to the secondary springs and the power valves in the carbs you are using.  The secondary springs for the dual quad carburetors need to be rougly half the standard single four carb tension due to the vacuum signal to each being cut in half.  Drilling and tapping the secondary diaphragm covers on non-dual-quad carbs so that a small vacuum line can connect the two vacuum chambers will help to insure both carbs are opening at the same rate assuming the springs are the same in both.

 

The same half vacuum signal scenario also falls in line for the power valves.  The old trick of using a pair of staples on each power valve to collapse or pull together some of the spring coils on the standard power valve to reduce the tension seems to be any easy fix if having difficulty in finding the dual quad power valves.

 

Maybe John can give some experience on what these carbs like in the way of fuel pressure?

Lorena, Texas (South of Waco)

Paul:

I believe Wally used Edelbrock carbs.

John - "The Hoosier Hurricane"

Jim; Tuners or rebuilders of the old Holley 4000 Teapot carbs are scarce as hens teeth. The only person that comes to mind that has raced them recently successfully, is Wally Kerstein out of Illinois. I don't believe he is on this site. Also, you could try over on the 1957ford.com site, for a fellow named Randy at- RLCpartman@aol.com He is into "E" code cars & has a rebuilder that knows his stuff in Wisconsin or Michigan.. Maybe when Ted or John "H" see your enquiry,they may be able to add to this..

Paul

I'm interested in communicating with anyone on the forum that has experience in tuning of the Holley 4000 series 4 bbl carbs. Especially, experience with the (2) 4 bbls in a racing (drag) application?

Thanks

Jim