Stumbling & stalling off idle - bad gas?
 

This is for a SBC 350. Car runs fine on the highway and in park, but at a light she starts shaking a little, then off-idle she shuts off. She starts right up after. This happened mostly on some short hills.

Put in some seafoam and filled the tank with premium, she is running a little better, she stays alive but still stumbles. Should I add heet and change the fuel filter?

carbureted or injected?

Carbed 1978 SBC 350.

Guy said car sat for 4 months without stabil.

:D would it have an reel rock carb on it?

Time to tare the carb apart and clean the crap out from today's Ethenol cut fuel, gas tank additive will not fully help at times !

Get a carb kit like a Walker and go thru it.
Give it a good cleaning and use the new accel pump included
Record the stamped jet sizes and primary metering rods

suspect some plugs getting wet-fouled. Carb redo with idle enrichment may help close the Primaries.