Welcome to the Stovebolt!
What else do you plan to do to the truck? I'm going to offer some answers but will assume as I do so that you intend to keep a basically stock inline and transmission. If you are swapping motors my answers would change.
There is a guy who 'drops' axles named Sid who will do your 3/4-ton front axle. That would be an easy way to get the front down. Check with
Sid.
The rear is a little harder but you're probably also going to consider changing the ratio and possibly the entire rear. The stock gears are 4.57 and little steep for running the highways with a stock motor. I once talked to a guy who swapped to a rear with 3.42 gears and his 216 would not pull the truck any longer. I'd suggest something in-between if you are keeping a basically stock motor.
Once you've decided what you're doing with the axle, you can use lowering blocks and a c-notch to lower the rear of the truck. Or move the spring hangers and use a notch. Or 'Z' the frame.
There are lots of other options but they fall into the complete swap arena.
Regarding the brakes I would suggest going Bendix if not disk. There is actually a disk brake kit for your REAR axle but none for the front.
The following link is one of the best DIY disk conversions for the 8-lug trucks.
John's Brake ProjectPost more about what you are doing and I and others will be able to post more specific responses.
