318 Engine stumble

Some thoughts
1) low fuel level,or
2) non-functional accelerator pump circuit,or
3) lazy transfer circuits,or
4) bad bowl-vent

All but the first one of these can be indicative of a bad T-port sync, usually due to too much idle-timing, but not absolutely necessarily.
> Reset the float level to the high side of the spec.
> Make sure the bowl is vented any time the engine is running.
> The Distributor should be getting it's vacuum signal from the SPARK-PORT. The Vcan should be inoperative at idle with ZERO vacuum measured on the sparkport. If you have a vacuum signal here with a stock or near stock cam, the primary throttle valves are too far open. Find out why.
> The PCV should be working as designed by the factory, and there must not be any vacuum leaks, anywhere.
> the secondary throttle valves should be closed up tight but not sticking.
> The engine temp should be more than 185, less than 205, the higher the better, and dead stable. If the temp is running up and down, something is wrong. You cannot tune the engine with this going on.
Now:
> The transfer port exposure, under the throttle blades, should be square to perhaps a little taller than wide. Make them so. After this is done,Do not change this setting more than 1/2 turn in either direction.(You have to take the carb off and flip it upside down to see this.) Reset the mixture screws as may be necessary.Then, set the idle speed with timing, somewhere between 6 and 16 degrees. Start at the low-end. Go up in two degree increments, until the engine is happy between about 550 and 650 in gear.Like I said; Do not touch the speed screw, more than 1/2 turn+/-, to fine tune. The idle should not jump up more than about 100 rpm when you take it out of gear. If your engine will not do this, something is wrong.
> Reset the pumpshot to begin at the slightest bit of travel of the throttle blades.
> Limit the power-timing to 36* or less, as may be required to stay out of detonation. Don't be in a hurry to bring it all in; if it doesn't come all-in until 3600 that will be fine......... at this time.

If the engine will not idle with the above rig-ma-role worked out, and it has hydraulic lifters, then we will have to take the carb apart.

I hope I thought of everything,lol.

done