I just bought a 69 Chevelle (L4-400 hp) from someone who lives on the west coast. The Holley street avenger carburetor (770 CFM) manual recommends a decrease in the primary and secondary jet size of one jet per every 2000 feet above sea level. The plugs are a dark black color so I am running a very rich mixture. I live at about 7000 feet. Does anyone know what the right jet size should be for this setup? Are the jets easy to change or should I find someone who is an expert in carburetors?? Any help would be appreciated.
tim
