Holley. 1904

I have a 56 s112 with a holley 1904 on it starts and idles great but when you accelerate it has a bad hesitation like it is going to kill I have had the carb cleaned 2 times with a new kit the only thing hat I can see on it is that the linkage on he side is really loose not sure if that is causing the problem bit I can not drive it till I get this figured out so I am looking for thoughts on what to look for

It's probably the linkage, in the 80s sometime the original owner replaced my trucks linkage with a cabled suspended pedal.

Will it hesitate, when you are sitting and not in gear? Linkage probably does not have much to do with it, but still worth tightening up. Have heard that there might be a "very small" orifice in the carb that becomes blocked(sticks in my mind that I have read that here several times) Wait for others that have these carbs and have rebuilt them to answer.

What is a "orifice"?

Something like this: http://www.google.com/url?sa=t&rct=j&q= ... kf4XV_IONw

also commonly called the "jet" as in changing out the jets in my carburetor.
Orifice refers to the opening, there are some deep in the Carb that can become plugged.

May also want to check for a vacuum leak. If the gasket under the carb isn't sealing properly, you'll have a vacuum leak and get an off idle stumble. Or if there is no problem with the gasket check all the rubber vacuum hoses for leakage.

Could be the vacuum advance or timing is a bit off, you have all kinds of critters to chase here.

For a stumble on acceleration, check the accelerator pump. With the engine off and the choke fully open, look down the carburetor throat. You should see a spray of fuel as you open throttle.

Dean

could be points, could be timing, check and eliminate each,

I'm thinking fuel starvation, which could be partially clogged fuel line, weak fuel pump, sticky needle valve, sticky float, or like Lloyd said internal clogged secondary jet, inoperative choke not opening all the way,,,list goes on

the only real way to solve it is to do a checklist and eliminate or fix as needed each possibility.

I'm likin Dean466's comment as a starting point. An easy check and the most likely issue. But if the carb was just rebuilt I am thinking that the pump would be new.