I HAD a problem of when you get on the gas the engin would cough just once and then take off as normal.
Don't know why ,But it hadn't done it in quite awhile but for the last week the problem has came back.
I thoudh it might be starving for gas so I changed ALL the filters.(air and gas)
A friend of mine said it was the vacuum advance. Hum????

This is a 77F250 351M TWO BARREL CARB AND A STANDARD TRAN
Thanks Don

 

Ah...The Infamous " Flat Spot"

Check the power valve and/or the linkage for it.

 

Check to make sure that the accelerator pump is squirting gas into the carb when the throttle is pushed.

 

I had that same problem on a 77 with the Motorcraft card on a 302. Also it was hard to start after it set a couple of days. It turned out to be the accelerator pump on the carb. I notices that when you steped on the gas it pumped gas through a weap hole on the bottom of the little plate covering it. Alos when it set gas would drip out of the carb bowl so it took alot of cranking to fill it back up before it would start.

The repair part was under $4 at AutoZone down the street.

 

I'M no machnic What is this, and is it a take to the garage thing?

The cargartor shows no signs of leaking when I changed the fuel filter.

 

The accelerator pump is on the front of the carb. It has a linkage that runs to the side of the carb where the accelerator cable hooks up. When you look down inside the carb barrels (engine off) and manually open the throttle, you should see two streams of gas shoot into the barrels.
You might also need to check the timing (loose distributor) and verify that the vacuum advance is working.