Have a 66 Thunderbird with a 390 4bbl. The carb that is on it is a 4100 Autolite with a 1.08 throat. I think these were used in Mustangs with 289. I need to know what the original equipment carb should be. Runs pretty good the way it is but tends to stumble a bit when hot and sometimes will die. I have installed carb kits a couple of times but not much changes. Maybe a little undersized.