OK, thought we had someone new. For the most part nothing is different as far as manual goes. In general, for all 62 verses 63 carbs, the 62 has a smaller jet and smaller needle, the 62 has a fresh air port (not vacuum) that hooks to the throttle retarder, the 63 has a “tower” on the float cover that is for the vent. I am assuming that they found gas splashing out of the 62 non tower vent? Other than that I don’t think there is any difference. I upgraded my cars to the 63 jet and needle. Actually, I modified my wifes throttle body and flows more air. to get it rich enough off idle I went to the 63 jet and 62 needle. As soon as my car is done I am going to build her a new stock carburetor with the 63 jet and needle.