brake booster and master cylinder

[keith1365]

I have touring classics c5 front calipers and LT1 rear calipers on a 68 camaro. I am currently using a manual set up with a 7/8 master cylinder. I am going to switch to a vacuum booster setup and am looking for opinions on what master cylinder to use. I am assuming I can find something off an older corvette that had 4 wheel disks. Any idea on what I am looking for?

[Apogee]

We typically recommend a 15/16 to 1 inch bore master cylinder with vacuum assist brakes and C5/C6 front and rear. Since your LT1/C4 rear calipers have the same piston size as the C5 applications, it should be the similar. The 67-76 C3 Corvettes have a 1" bore MC with a deep pushrod hole that a lot of people use, but you can run a late-model LS1 F-body unit or S-Truck unit and save about 6-7 pounds over the C3 MC.

How much vacuum do you have at idle?

Tobin
KORE3

[bochnak]

I am currently using a manual set up with a 7/8 master cylinder.

I plan on starting with a manual setup. What is the application that uses a 7/8", and how did it work out?

[keith1365]

Not sure of the application. I started with a 1 inch and that was not good. Way to much pedal effort. I bought from front set up from Noel at Touring Classics. He set me up with the smaller master cylinder. It works ok but the pedal effort is still a little high. To get the brakes to lock up you really have to stand on them. I thought about trying a pad change first since I am running the stock pads.

[bochnak]

Thanks.

I found a 3/4" & 15/16" app.