Here is another source for info and parts - https://www.carburetor-blog.com/article-categories/holley-4000/

20Hg steady indicates a healthy engine (IMO).

Maybe make sure the primary throttle blades are not hanging on the intake carb pad bores and/or carb mounting gasket, the throttle shaft bushings are tight and the throttle blades are aligned correctly and not bent (some one else may have been in it).

Is the choke cross-over tube still connected and functional? Follow the curb idle procedure outlined in the WSM exactly.

Listen to TED and let the board know what you find as this will be helpful to others.

[U]FORGOT - CRS ...

Make sure the CHOKE ASSY is fully functional and the FAST IDLE CAM drops fully before setting curb idle.

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Thanks  Kultulz  for link to info.

When it stalls, maybe it is going lean.
  Are all the idle transfer slots/ports clear? (2 or 3, depending on gen, in each primary port)
  Check the air bleeds on the top cover and ensure they are not blocked. Some carbs have a very large washer there and may be closing them off. There should be a small gap.
  Check the accelerator pump rod has vent holes, they should both be open in warm weather.


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

Thank you for the replies.   I am going to try to tune it the way it is before I drill anything.   It's been raining here 4/5 days a week for the past couple of weeks.

Whereas the model 4150 & 4160 Holley four-barrel carbs do have an adjustment for the secondary throttle blades, the model 2140 & 4000 Holley 4V carbs do not.  With that in mind, then adding a pair of holes in the throttle blades is an option.  Before doing that though, hold the carburetor up to a light source with both the primary and secondary throttle blades completely closed and ensure that no light is seeping past the blades.  If there’s light, then you have some extra air getting past the blade or blades that will need to be corrected before going any further.

While it’s customary to add the extra ‘air’ holes in the primary blades, I do not see an issue with putting them in the secondary blades.  I personally would start with 1/16” holes as you are not going to need much and give that a try first.  Easy enough to drill the holes larger but much tougher to make them smaller.

Lorena, Texas (South of Waco)

HERE - https://www.mustangtek.com/Library5/PDF/Holley4000.pdf

It should have all of the CARB SPECS. If not will be found in the FORD/BIRD WORKSHOP MANUAL.

Check all linkage(s) and adjustments. Remove throttle linkage(s) while adjusting or adjust on bench.

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Manifold vacuum is steady at 20.

The timing at idle in park @ 800 RPM (This goes down to about 500/550 RPM in Drive), 10 BTDC (this is with the vacuum port on the carb plugged).   The car is running fine, there could be internal engine wear,  I don't have documentation for whatever has been previously done.  I believe there was a rebuild in the recent past.........  Whatever is going on I am not ready to rebuild the engine.

I didn't touch the throttle blades on this carb. I have a plug with a gasket and thread sealer for the spark advance valve.

I had the carb off yesterday.   I loosened the idle adjustment screw and the vacuum port hole was covered.  The slightest adjustment seemed to expose the vacuum port, which is why I was considering drilling a hole in the throttle blades.

When you say: " Sometimes just cracking open the secondary side throttle blades is just enough to allow the primary blades to close enough to shut of the ported vacuum signal at idle."   How would I do this?   Is there an adjustment for the secondary shaft/blades?

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With the distributor vacuum unhooked, what is the initial ignition timing and at what rpm?  The presence of vacuum at the ported vacuum port of the carburetor at idle is indicative of the primary throttle blades being open too much.  Several things can contribute to this including the throttle blades in the carburetor not being properly aligned, leaking spark advance valve, idle fuel mixture too lean, the valve lash set on the tight side, the ignition timing incorrect, poor piston ring seal, leaky valves, worn valve guides, breaker points gap, flat lobe on the camshaft, worn timing chain, etc.

Drilling holes in the primary blades is usually done as a last resort.  Sometimes just cracking open the secondary side throttle blades is just enough to allow the primary blades to close enough to shut of the ported vacuum signal at idle.

As a general rule, I do not remove the throttle blades on the model 2140 and 4000 Holley 4V carbs when rebuilding.  When necessary to remove those blades, then when reinstalling them, the carburetors are held up to a light to ensure that all four blades do completely seal to the bores when seated shut.  It’s important that the blades be reinstalled with the correct side facing down as there is an angled chamfer on the blade edges to ensure a perfect seal.  Even if rebuilding the carbs and not removing the blades from the shafts, it’s still a good ideal to check that the blades do seal completely when closed as even a backfire can distort the blades.

Lorena, Texas (South of Waco)