The frames are not the same. The 3/4 has a longer wheelbase and
the rails are parallel from the cab on back, where the 1/2 ton frame is tapered from front to back.
The front springs are the same for both models.
You can swap a 1/2 ton front axle in place of your stock axle and get a 5 lug disc brake kit or use 5 lug car hubs if you don't want discs. And of course you can change out the rear for a 5 lug rear axle. These mods would really make your truck more like a car than a 1/2 ton.
