[Captainfab]

To keep things simple just use a master cylinder for the '78. Hopefully you grabbed the proportioning valve also. For the booster, that all depends on how you want to mount it to your firewall. The booster bracket I sell does not require drilling any more holes in your firewall. Other boosters and mounts require drilling holes to mount.

It looks like you got the entire steering linkage as well. I would suggest using the '78 idler arm, but you will have to drill 2 new holes to mount it. Using the complete steering linkage, simplifies the installation and when it comes time to buy replacement parts it is easier to remember whar year if truck to ask for parts for.