This may sound kinda dumb but I thought I had carb problems because I had the same hesitations. Check and make sure your spark plugs are good. My engine is old and tired so the worn rings and such had caused the plugs to foul, yea they all looked like someone had taken them and rubbed them in dirt/grease and put them back in the heads. I replaced them and it runs great. I'll be so glad when I get my new engine is finished!
'79 K5,13 1/2" lift, 39.5 TSL's,15x12 Eagles,350,t-350,warn 8274,39.5 Boggers for wheeling!