The stumble under acceleration could be because your float level is too low, and the carberator can not deliver enough fuel to keep up with demand. Or it could be because of wear on the internal parts of the carb. But it could also be ignition.

If your carb has not been overhauled in the last sevaral years, than I recomend you overhaul, just for grins. The carb needs to be periodically overhauled to keep it in top working order. Their is a chance that this will eliminate your stumble.

This is your carburator: http://holley.com/0-80319-1.asp
This is your carburator's overhaul kit: http://holley.com/703-47.asp
This is Holley's technical library: http://holley.com/TechService/Library.asp
This is an exploded view of the 4160: http://holley.com/data/TechService/T...ded%20View.pdf
This is the float adjustment procedure for the 4160 (follow the Duracon (plastic) procedure): http://holley.com/data/TechService/T...ded%20View.pdf

The rebuild is actually very intuitive, simply replace what you disasemble if the parts are found in the kit. The kits can come with extra parts meant for other carberators. The overhaul kit commonly retails for about $50-$75 at NAPA or other mainstream retailers. I have found them for $25 on Ebay stores.