Looking at the image, i'd replace plug wires as a bare minimum, as it looks like you have had some replaced. If those are carbon fiber plug wires, that in essence could be the rough idle issue. If you are keeping the truck replace the plug wires with solid wire .

 

Pics look like that has not been fired up in a VERY long time!!

 

Yea, I can relate, son in laws 71, now

 

Hi Tony,

I am very familiar with the old Chevy C-60 series medium-duty trucks. Chances are that it has a specialized Holley carburetor and a non-vacuum advance, weights only advance type of distributor, and likely also a governor/regulator system that keys off of the carburetor, for keeping speed control under check.

I'd ditch the points-style ignition distributor for an electronic ignition system, and find a vacuum advance distributor too. We were always replacing the points/condensers every MONTH on these old trucks, and the AIR pumps cost lots of wasted time and money,as they were not designed for all the dust that a medium duty truck takes in, but for light-duty cars/pickups that dont see all that much dust, dirt, grit and grime.

If the truck came with an old A.I.R. air to exhaust manifold air injection pump system, I'd ditch that as well. Those old AIR pumps dont like dust very well
and I no not why Chevrolet/GM ever put them on a medium duty truck, as they were not required to meet the smog standards, like cars, even way back then.

If you do these things, your fuel mileage will increase, and the truck will run much better, _and_ cleaner, as well. Yeah, it'll cost a few bucks, but if you keep it for long it will pay off.

 

I agree. A carburetor kit and a very good soak/cleaning is likely in order. Looks like a two-barrel, so it shouldn't be that hard to do. Points are likely in need of replacement as well. Those old carbs used to develop air leaks pretty easily. Thankfully, fuel injection makes carburetors a thing of the past.

 

Small block 327 V8. I am used to the 366 and 427 cubic inch big-block engines of the day. Yeah, it has a governor. Those were a major PITA. Thats an oil soaked style air cleaner. Need to clean that up real good. Man am I getting old or what??