https://www.gearvendors.com/hrdodge3s.html
there are club members who do transmission work professionally (full time) or in the manner of a professional (on request), there is a bit of work to fit the overdrive to the transmission.
brakes
many kits for disk front end on mopars, some better than others.
my car has factory disks so i can't really recommend a specific kit as never had one.
all comes down to the right peddle ratio and bore size of the master cylinder.
you can do it with OEM parts off other models.
i don't think you need rear disks, trucks have drums
so can we....
you can retro fit the ECU pressure pulse unit and master cylinder off a B van, and have rear anti lock drum brakes, but its a bit of a fiddle
new hubs rotors and wilwood calipers/Wilwood mounts for drum spindles would do you fine
get the wilwood calipers with the rubber seals
think you should have dual circuit master cylinder. you need to pull the residual pressure valve out of the port for the front brakes
you own a 68-70 B body mopar
i.e dodge and plymouth B body cars for these years, are all the same under the skin, apart from any option the first owner wanted
each company had 3 or 4 price points, they called the B Body model at each price point something different, and just varied trim and size of engine to match the customers pocket.
a Satellite a Belvedere a Road Runner a GTX all have the same body and general mechanicals
so when looking for parts B body is key.
Dave
Nice car 
