This subject has been around before, there are a couple reasons to keep the original carb on this model. 1. The linkage on the 62, as well as a few others of this era, is designed to PUSH the throttle plates open and most later oem carbs, as well as nearly all the aftermarket stuff like the Edelbrocks, Holleys, Predators and Demons PULL to open. Its not impossible to overcome this, but its another wrinkle to deal with. 2. The AFB is perhaps the simplest carb on the planet to rebuild. The two problems that would take the most ingenuity would be excessive throttle shaft and bore wear ( causes a vacuum leak around the throttle shaft bores ) and a porous main body ( fuel leaks away after shutting down, sometimes over the course of several days. 3. Cost...a Demon aint cheap! Its also built more for a higher performance engine and vehicle application than any of our Imperials. If the AFB is indeed suffering from one of the above listed problems, Holley can rebuild it for you. Most people dont know that Holley can and will rebuild carburetors, even ones they didnt originally build. Holley's website can say more about that than I can. Just my 2 cents....if you do install the Demon, or whatever other carb, Ill give ya 20 bucks for the 62 carb you have now! Mikey 62 Crown Coupe