Anyway, you have to take the manifold off to work on it. A machine shop or drill press will be your best bet unless someone here has one. you can as said, tap to next size. They sell stepped studs; or drill out the carb hole. Inserts are too much work and money when you can just drill and tap. They are mostly for aluminum.
I’ve repaired a whole bunch of messed up bolt and screw holes. I disagree with most of the above quote.
I would repair it on the truck, a carb bolt hole in the intake is very easy to get to.
Drilling, tapping and installing a Heli-Coil is easy enough if you can work carefully and a small kit with tap, drill, and installing tool won’t cost that much and you can use it again many times, when necessary replacement inserts are cheap.
