If it was mine here's what I'd do:
Hydraullic brakes, '35 Ford 16" spoke wheels, dropped axle, warmed over Model B or C 4 banger, '39 Ford transmission, V8 banjo rear end on the stock Model A spring, LeBaron-Bonney stock mohair interior. All changes are reversable, but the car would be more fun to drive at highway speeds and look cooler with these mods.
Nice find, by the way!