This is a complete bolt-in kit for 1950 and 1951 Cadillacs. This kit 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 different 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 checkout  and I will send the correct proportioning valve. 
 
It will have the pedal feel of a modern car- minimal effort required with a positive and firm feel. 
 
Installation is fairly straightforward- likely no cutting required, this kit doesn't involve anything permanent that can't be undone in a couple hours! You have to remove the driver side air box, vent door, master cylinder, master cylinder mounting plate, and then this kit bolts in. Brake lines are included and pre-bent, but the rear line will require you to splice into your original system.
 
The firewall box has water drain spouts, and a new drain hose is included. water will be able to drain out from the windshield area just as the factory. 

This kit comes with everything, including a proportioning valve, brake lines, and hardware. All you need is brake fluid and a port on your intake to plug into the vacuum. 
 
Included parts: 
Firewall box, powder-coated black 
The Brake pedal bracket goes through air vent hole 
Brake pedal W/ Bushings and rubber pad 
GM-style brake booster
GM-style master cylinder 
All new high-quality bolts 
2X 3/16" brake lines- custom cut, bent, and flared
Proportioning Valve + metal lines (mounts beneath MC, pictured)  
3/8 Vacuum hose
Water drain hose, same style and function as factory 
Misc. hardware 
 
Brake booster options: 
-9" single diaphragm vacuum booster in gold zinc. This is the best option for drum/drum brakes. Anything more will feel too powerful. This is what's pictured here on the website. 

-9" single diaphragm booster, in chrome, otherwise same as above option 
 
-11" single diaphragm booster in varying finish of gold, zinc or black powder coat. This is the best option for disc/disc or disc/drum. This booster is considerably more powerful than the 9" booster. Our supply of the finish is inconsistent, so we provide whichever finish is available. 
 
-Hydroboost. This booster uses power steering fluid rather than vacuum. It is our most powerful booster, and overkill for most applications. The booster housing is longer so it may cause minor interference issues. This is best for high-horsepower applications without a good vacuum source and with front disc brakes. 

Proportioning valve options: 
-PV4 works for drum/drum or disc/disc. It proportions the brake fluid pressure equally front and rear. 
-PV2 works for disc/drum. it proportions the brake fluid pressure with a front bias.