I have a 1955 t-bird 292 ci what be the right main jets size for the Holley 4000 tea pot carb?

carb has stopped up jet or bad plunger Rework carb or replace Good Luck Mike L.

Hey Darin...have a look down the carb, while the engine is not running and check to see if your butterflys are fully opening under wide open throttle.

Sometimes if adapter plates are used they hang up the secondaries.

For those like me with a good old fashioned Holley type carb, here's a real nice video on the basics. He's gonna be doing more in-depth videos in the future. This cat flat out knows carbs!

This is a complicated question. It depends on how you plan to drive the car.
A 500 cfm Holley would probably be more than enough unless you are using the car on a track.
300 cfm can probably work but may not give you much more performance than a stock Quadrajet.
Holley is the best for modifying a carb to a specific engine. You can pick the jets and other parts to your needs.
Quadrajet was stock on GM.

When attaching vacuum lines, you need to remember only one thing. Mark each hose when you remove it from the original carb (quadrajet?) Hoses that attach to the baseplate are at full vacuum and should be returned to a similar location or to the manifold, using a "tree". Hoses that are connected to the body of the original carb only see vacuum when the throttle is opened. Those can be attached to the fitting on the right side of the front metering block. Most Holley carbs have no provision for the valve located at the front of early Q jets (bowl purge) nor do they have any electrical connections except for the choke mechanism.
The most important vaccuum line is the one for your power brakes. Make sure that one is firmly connected either to the rear of the carb baseplate or the manifold. All other lines are nowhere as critical as that one is..

that holley would work just fine, you may have to change the jets, but that is easy

As you know, you have one of two things going on. it is running too rich or too lean. Run it hard for 15 minutes pull the plugs and check for black, wet looking soot = rich. Brownish, whitish dry looking soot = lean. Be sure your vacuum advance on the carb is hooked up to the proper port. Check the full advance of the timing with a light to be sure you have proper advance during rev up. You want 22 degs. full advance. If you have a pull choke try to close the choke to see if that will level out the hi end. If that works you are running to rich. adjust as necessary to lean it out. Too big a carb can also be your problem. For the best carb to engine size double the cubic inch of you engine. If your engine is a 290 ci you max size carb should be approx 550 cfm, Now if you engine has a hi rpm cam profile you have to factor in needed cfm at hi rpm. Thats why such and engine for racing will not have good bottom end or low rpm power. Sounds like you have just the opposite going on. Which can still be caused by a over sized carb. Too much fuel not enough air or room in the engine to burn it.

Most likely you have a Holley carb. You may have a 460 engine. If you have the carb with a big vacuum pot in front of the carb, then you have a RPM governor. The RPM governor will work against the 4 barrel.

The main mixture for the idle jets can be adjusted like any old style carb. You may have plastic caps over the idle screws but take them off. Then use a vacuum gauge on any intake fitting and proceed to read the vacuum level as you turn the mixture screws. You want the mixture to reach a maximum RPM, then evenly turn the screw in until the RPM drops slighty and then balance for smoothest idle.

After this step adjust curb idle and see if this helps when the 4 barrel kicks in. Holley has different springs for the vacuum actuated secondaries and they are color coded. If the carb is original it should be right, but if the carb is of unknown origin you can check the proper vacuum spring, main jet, power valve and so on in a good Holley book. The mechanical secondaries are also listed with clearances to hand adjust.

By adjusting the mixture screws you have set the engine to idle just below peak vacuum pressure. This means you should have more vacuum to work the secondaries.

Baseline would all depend on what its going on big block or small block if its a small block a 850 is too much carb. because you have to jet it down so far to get it to run right and not foul the plugs because of to much gas unless its built 650 or 750 would be the right carb for the street you can start with 70 in front and 72 in rear is a good starting point, the thing to do is get a jet kit from holley and experiment with it.

hesitating when from a standing start, then running well can be caused by having too big a jet size. I dropped the size of the jets on my Holley 4V, and it solved that part of the problem. The accelerator pump will push in too much gas, momentarily "drowning"the engine til you get enuff air to mix with the gas.