This is a complete bolt in kit designed to work on 1980-1990 Chevy C70 and similar trucks that gives a firewall-mounted Kodiak / Topkick style hydroboost booster and huge 2" bore master cylinder. The 11" dual diaphragm vacuum boosters we sell for C60 trucks just don't cut it for the heavier trucks. 
 
It's important that you confirm fitment before ordering by comparing my pictures and measurements to your truck. There may be variations in these trucks I am not aware of. This kit is meant for trucks that have a firewall bolt pattern of 3.75" by 3.75" and a depth from firewall to brake pedal of 9.4".

This does away with the hydroboost over vacuum booster system. This booster installs in about an hour and requires no cutting or permanent modification. It works with your existing brake pedal and existing power steering pump. Kodiak hydroboost do not plumb in like other hydroboost you might be familiar with. You leave the existing high pressure  hose that goes from pump to steering box. Add in a new high pressure hose (included) that runs from steering box to booster, then there is only one return line back to the pump. 
 
C70 applications have a long spacing from booster to pedal connection. Our boosters are special made with threaded detachable ends, and we provide machined threaded extensions to accomplish the correct rod depth into the cabin.
 
Tag Axle
Trucks that have a second (tag) axle have a secondary brake booster and master cylinder that feeds the rear axle. Our firewall-mounted system does not replace this secondary system. We have limited experience with this. Please review that system before purchasing, but it can likely remain intact and operational with the modern brake booster serving the primary axle. Using the new master cylinder to serve two rear axles will cause an out-of-proportion system, and the front brakes will do all the work, with the rear brakes being hardly activated

Installation
The kit is designed as a bolt-in installation and works with the factory brake pedal 
 
Included parts with this kit:
Firewall booster brackets, painted black
Kodiak style hydroboost
Kodiak style 2" bore dual output master cylinder
12 volt backup pump and relay 
High pressure hose and low pressure return line for hydroboost
6AN adapter fittings for high pressure plumbing 
Custom bushing designed to mate SD booster eyelet to factory brake pedal
High quality grade 8 hardware for entire install
Flare adapter fittings- to connect standard 7/16" inverted flare fittings to the master cylinder (common on 1/4" lines)
 
These brackets are designed, laser cut, and formed right here in the USA. The parts supplied with them are top quality