This is a Chevy 6 with a mild cam,more compression and headers.I modified the stock intake to accept a large base Rochester 2G carburetor.I enlarged the carb idle restriction "jets" and a main jets a few sizes for best performance. The intake is water heated.The timing is set at 10 initial with the total mechanical timing of 36 degrees.Has a vacuum advance.The engine runs very nicely,no bogs,no flat spots,excellent throttle response at any rpm,starts instantly hot or cold,never any carb flooding,slight idle lope with 18 inches of vacuum and makes good power for what it is...except for one small issue.
I'll explain it this way.You're sitting in the truck holding the engine at let's say 1600 rpm.Take your foot off the gas,the engine speed drops down to around 400 rpm,stumbles a bit,then returns to the normal 700 rpm idle.If you ease off the gas pedal slowly it returns to idle just fine.On the road this means when coming to a stop unless you fiddle with the gas pedal,the engine does it's stumble trick. It never actually stalls but is a bit annoying in traffic.Once the thing is idling at 700 rpm it's very steady..No apparent vacuum leaks
The brass carb float is set to 3/4 inch at the float seam as shown in Rochester repair manuals.I have moved the float up and down several times with no difference in the idle stumble.The carburetor never gets hot and doesn't ice up......Throttle shafts seems to be ok,no more or less play than many other carbs I'messed with.