Stock Rear End Size and Gear Ration in 71 Demon 340

If you can't figure out from fender tag or build sheet you could just jack up the rear of the car and spin the wheels, see if both wheels turn the same direction (if yes, you have Sure-Grip) and also count how many times the driveshaft turns with one full rotation of the rear wheels. IIRC 4-speed cars usually came with 3.55 or numerically higher gears, starting ratio with 3.23s is kinda tall with a non-OD A-883.