UPDATE

replaced the 261 specific rochester with a rebuilt zenith from a gmc 270... truck runs much much better... pulls 3rd and 4th gear easily

also re-set timing to ball on flywheel, re-adjusted valve when at triangle on flywheel, adjusted carb by vacuum method, and added pertronics electronic ignition

overall starts, idles, and runs out very well.. based on the results from each change it looks like carb change made the biggest difference

thanks everyone for suggestions and help

Old Truck addict
1950 chevy 1 ton napco
1956 gmc 1 ton dually napco
1954 chevy 3/4 ton napco
1957 gmc civil defense napco panel