Mike's kits have only the screw in type seat. Other kits have both types and only one needle. Often, you can see the two seats, displayed with the needle between them, in their ads. Oddly, Mike has the spring for the press in seat, sold by itself.

Hello  I have been looking into buying a a carb kit for a 56 lincoln 4000 teapot carb that Iam coverting to a clone S/C carb.   I was concerned about  the fuel inlet needle and seat valve. This carb used press in type. Called Mikes and was told press in seat type was not available BUT screw in type would work. I had a core 4000 with treaded  type, would not fit. So moved on to Dayton kit they say have both in their kits, what is going on? The Lincohn  carb had a fiber gasket on the fuel  transfer  (?) tube (tube that connects throttle body to fuel bowl that uses a spring on top end) was told it uses a rubber O- ring both ends. Top end of tube has a grove for o-ring but not  on throttle body end, so which one is correct? Maybe should have started a new post.

Mike's Carburetor" has the Holley parts lists for '55 & '56 Ford 4000 carbs. These show Holley part #'s for each and every piece. Size of all holes in jets etc is given. The '56 sheets are specifically for the T-Bird. I hope that just means T - Bird engine. These lists are extremely useful, and free!
I recently bought a couple of Holley Master kits for 4000 carbs used on "White" fire trucks and other HD trucks. These are pre-funny fuel, and soft parts are dried out some anyway, so they were refreshingly inexpensive. The jackpot was that the fire truck kit contained a pair of the "Duck Bill" discharge jets. All the kits have economizer valves. I expect the calibrated drillings are different from the sizes for Ford cars. I'll live with that, or deal with it.
There probably was an SAE pa"per about the Holley 4000. These were $35 each a few years ago; for a shabby photo copy, and a dire warning about copyright policy. I've bought a few about engine development and McCulloch superchargers. - excellent material!
The earlier 2 barrel concentric Holley was still used in the '70's on army trucks. It met some military spec about operating at extreme angles, and was sold for use on dune buggies, too.

I had no idea that the Teapot was used on other makes/applications until the 70s. My brother is a mechanic, and he had never seen one before. 

____________________________

Rob. Thanks for sharing that patent info. Interesting on some of the development that was taking place on those Holley Model 4000 carburetors long after being used on the Ford cars.  Both GM and International Trucks used the Holley 4000 (Teapot) carbs up thru the early Seventies so there’s a good chance some of the Sixties patent information you found was used on those applications.

Lorena, Texas (South of Waco)

I have done quite a lot of Patent search on it and this is what I found ... so far: (in numerical order)
------------->
The 12 patents cast on the fuel bowl are marked with the ^ symbol here.

One casting, ECZ-9510-L List 1162-2, Cast on bottom inside: 6R-1259-B5 (unknown if any others have this) it has 3 more (15) and are marked with two symbols. ^^ (also the cover has the following date and variation stamping: 631 (58) but unknown if it was the original. I would hazard a guess that it has to be the dual carb setup though! ???


All others are cross referenced or some way related. (The Carb or the Patent applicant or Patent references etc.)
--------->
2240194^ - Dual Downdraft Carb 1941
2249446^ - Spark Advance 1941

2313258 - Two Stage Carb 1943

2355881^ - Governor 1944
2356679^ - Governor 1944
2381550^ - Governor 1945
2381610^ - Vacuum Adv 1945
2406087^ - Governor 1946
2415508^ - Engine Governor 1947
2416110^ - Governor 1947
2538569^ - Choke Valve 1951
2547873^ - Combined Carb Choke and Nozzle 1961
2621641^ - Vacuum Ignition Mech. 1952

2698010 Vac Spark Adv

2737375^^ - Dual Carb 1956

2745645 Dual 1956
2766024 Dual Sec Vac
2826400 bleeds
2827269 Idle Control
2846202 Mixture Control

2856168^^ - Idle transition 1958
2902307^^ - Choke Spring Retainer 1959

2905162 Vac Adv
2947297 Distrib
2947509 Rubber Dashpot
3007682 Choke 4150 carb
3021828-A_I Spark Control Valve
3033947 Points
3051150-A_I Auto Spark Advance
3381674 Crankcase Vapour Control


3223391 - 1965. This one is different in that it is an improvement to the secondaries that seems to never have been installed. Or at least I cannot find any that have this done.
Enjoy!
R


1936 Ford 3W Coupe : 56 T-Bird 312, 47 Packard 3 speed, 40 juice brakes.
1968 Merc Cyclone FB GT 390, Getting a better front clip!
1977 Ford F-250 Supercab RWD Explorer Long box.
1976 Chev Camaro RS LT
Future rebuild : 1949 Ford F-1

Very informative. Thanks, Ted. 

Just my opinion here.  The needle seat assembly being threaded versus spring loaded would have no bearing on the performance attributes of the model 2140 and 4000 Holley carbs.  Keep in mind that the spring is on the pressure size of the needle seat assembly and if there was an increase in pressure, it would simply add to the spring pressure in keeping that assembly in place.

Some history here.  Holley was late to the show with a 4V carburetor.  Carter and Rochester were already making four-barrel carburetors when it was decided that Holley needed one and came out with the Holley model 2140 4V carburetor.  Those carbs were introduced on the 1953 Lincolns and then carried over to the 1954 Mercury and 1954 Ford Police cars.  The model 4000 carbs were introduced for the 1955 models and moved the choke plates to a point above the venturi rather than within them while also having an improved secondary fuel metering system.  But the flaw of having a single fuel needle seat assembly in the 2140 and 4000 carbs reared its head in that a single needle seat could not supply enough fuel for the higher demand horsepower applications.  The Carter and Rochester 4V carbs of that time period already had two needle set assemblies and those were already a step ahead of the Holley 2140 and 4000 4V carbs when it came to providing adequate fuel for the higher horsepower applications.  Added to the single seat problem of the 2140 and 4000 carbs was the very small fuel reservoir for the fuel which just compounded fuel delivery issues.  That fuel delivery issue with the 2140 and 4000 carbs was rectified with the introduction of the model 4150 4V carbs in 1957.

Lorena, Texas (South of Waco)

I'm rebuilding a Holley 4000 and have become interested in the spring loaded float valve seat, vs screw in type. I wonder if the idea could have been to allow the seat to lift, when high speed operation increased fuel pressure. As they were made, would this bypass the inlet needle and the small passage where it seats; allowing fuel to gush into the bowl. This would permit the use of a seat with a very small passage, (better for controlling fuel level in the float bowl). At the same time, when the seat lifted, plenty of fuel would be available for high speed operation.
I realize fuel pressure would have to increase with high speed operation; either through an engine driven pump that produced low pressure at low speeds, fitted with a heavy pressure limiting spring, or a simple vacuum controlled electric pump.