MoParGuy - please do not judge all Carter carburetors by the smog-friendly AVS. It was (opinion) the worst 4-barrel Carter ever made. We refused to rebuild them because there was a 100 percent probability that the customer would have issues. The carb was designed for smog emissions. Any performance, driveability, economy, etc., was a secondary consideration. Chrysler V-8's, from a smog standpoint, were dirty, and required special carburetors to pass smog emissions. Chrysler used these from 1968~1971, and then they were discontinued. Chevrolet tried them on one engine in 1966, and later suggested they be replaced with the 1965 carburetors.
By contrast, I have two genuine Carter AFB carbs on one of my shop trucks (advertising, but performance and economy as well). These work with no issues in high 90's, low 100 degree days in Missouri. I can get real gasoline, but have calibrated the Carters to run on the cheaper E-10, which is what I run in this vehicle. I did add an electric fuel pump because of hard starting when the ambient was in the high 90's.
The Carter AVS, along with the Rochester B, might be the best excuses for efi
On a more serious note, if I had to traverse multiple altitude "zones" daily, I might think about the possibility of considering efi.
Jon.
