Hesitation problems

Either A your carb is too big for the cam and heads and your engine loses all airflow (vaccum) when you open the throttle completely too suddenly, or B its too lean to compensate for the sudden rush of air, you may have a bad, I believe its called a power valve (the thing with the arm that moves when you floor it to give it extra gas) check to make sure its moving when you rev it, maybe a bad diaphram inside. if the problem occurs in park you can hold that down yourself and rev it to see if it goes away. or C you could just simply be too rich and overloading the engine with gas too suddenly for it to deal with it.

all this of course assumes you carb doesnt need a rebuild or a fuel filter or something, and that you havent gotten the needles way out of wack trying to fix it.

edit: forgot the ignition stuff, make sure its all working right obviously, but like you mentioned retarded timing can cause that stumble because the engine literally has to catch up with the fuel and air when you hit the throttle.
so check it to see if it needs advancement.

power valve, that the term I couldnt remember, thanks pabear

SadbutTrue said:

When i floor it, at just about any rpm, the car stumbles before accelerating. I'm going to mess with the timing (should I advance or retard it?) and the fuel/air screws but other than that I do not know what it could be. Coupled with my transmission going the way of the dinosaur, it makes for some really nasty shifts and such.

Any help is appreciated

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I would check your accel pump stroke, it's eather to lean or to fat.
You should get that squirt of fuel just before the blades open.
I have my 600 holley set so that I can roll along at 1k rpm in first and
mash the petal and Fry the rear tires.

PB

How about just changing your jets. I had almost the same problem when I took off, it would flattened out. I went a step down on the jets and it sloved me problem. Also you might want to change the rods also. Just a suggestion

I was having the same problem with my 289, it was ok if I accelerated real slow, or under half throttle... over that it would stumble at first, then go. I changed the spring on the accel pump linkage with one that was a little taller, and had more tension. This cured my hesitation just about completely.

I had the same problem in my car. I took the tools i needed to abust the accelerator pump and air fuel mixture and went down the road stomping on the gas. My neighbors didnt like it but there over it now. I would put some money on it being your accelerator pump (If you carb not too old).