This is a complete bolt in kit that uses a modern power booster and dual circuit master cylinder mounted to the firewall using the bolt holes for the factory air box. It includes a new brake pedal that swings from a higher location (looks like it could be original too). A modern GM booster and master cylinder give a significantly improved braking feel and power while adding safety through the dual circuit system. 
 
This can be used with factory drums, disc/ drum or disc/ disc. Let me know what brakes you have at check out and I will send the correct proportioning valve. 
 
Installation is fairly straightforward but it does require cutting of the firewall behind the air box (you can always put your original airbox back on and it would never show) and drilling of 3 lower screw holes to allow for heavier 5/16 bolts. This takes about 2-5 hours to install depending how well equipped the shop, rusted original parts, etc. You have to remove the driver side air box, master cylinder, original bake pedal, cut out an area about 3" wide area to make room for the pedal linkage, use nut-serts for all but the bottom 3 holes, and then this kit bolts in place of the firewall air box. By replacing the air box, you do lose the air and heat functions on the driver side. The passenger side air box is of course unaffected.
Please know that some Oldsmobiles have a very large metal air ducting underneath the dash and this kit requires that you remove or modify that air ducting for clearance. I have not personally installed this kit on such a car so I do not have pictures or exact instructions. One look under your dash should tell you- it is a particularly large metal air ducting piece between the firewall and dash.
 
This is only for a 1955 or 1956 Oldsmobile Ninety Eight or Eighty Eight.
 
All metal parts are CAD designed and cut on a laser table for consistent high quality results, then powdercoated in satin black.