idle rich, then leans out on highway?

bigger gap needs a hotter coil. What year slant, all dont require the washer. Slants that run good all have 1 thing in common: Properly adjusted valves! They will mess things up as much as a poor float level in a Holley. Get her hot, then adjust valves, then start working on ignition. (1920) The fuel level is set with the carb inverted, got to take it off for that. Low compression is not that hard on the ignition, so even a sub par coil will light it off. If you want to run a better spark plug, get one with a longer nose, I think AMC smog spec (NGK ZFR5N, with washer removed) it puts the electrode farther into the cylinder for better burning. and for the choke...inspect carefully. Fully open, unloading properly at WOT? Id ditch it for a cable.