If I remember correctly, smog engines were jetted leaner, which made them run hotter. This was compensated for, partially by the air injection pump, which helped keep things cool.
No, it's the opposite. Air injection makes the engine run hotter, not cooler. It's because unburned fuel meets injected air, catches fire and burns in the exhaust ports of the cylinder head. This puts a good deal more heat into the metal.
I'd remove all the smoggy stuff, and use a carb and distributor from a pre-smog motor. This is easy for me to say, though, cuz I'm not familiar enough with the actual what-will-work part.
Yeah, guessing isn't a good way forward. In the first place, using a distributor from a "pre-smog" engine would mean giving up electronic ignition and going back to breaker points -- yuck! In the second place, several of the best slant-6 distributors (in terms of advance curves out of the box from the factory) are from '76-'77, right in the middle of the smog era.
