Whichever motor you put in a '62, plan on notching the shock towers for header clearance. A 289/302 Ford would, as Matt said, be a much easier and probably more economical swap. You should also update the front suspension to 5 bolt hubs and disc brakes. A narrowed 9" Ford in the rear with either drum or disc brakes would more than handle the task. Many of the Mavericks had 8" rears with 5 bolt wheels. For just a street car and 8" with 5 bolt wheels will be fine. Slicks, big gears, and ladder bars will take their toll on 8" rears but they will hang in there pretty good if they are set up right.