disc brakes

[camarotale]

when you change from front drum brakes to disc brakes on a 68 camaro, is it necessary to change the master cylinder

[Tod74]

YES. and lose the factory proportioning valve/distribution block.

Drum brakes have residual valves either in the master or prop block that keep the fluid from being forced back toward master cylinder by the springs.

[camarotale]

I did remove the prop block and that is what makes me wonder if a change in master cylinder is required . Is there a difference in masters from the factory between disc and drum that will help my stooping.

[Tod74]

I did remove the prop block and that is what makes me wonder if a change in master cylinder is required . Is there a difference in masters from the factory between disc and drum that will help my stooping.

Disc brakes take more volume so you need to swap masters.
I just changed my NOVA this fall. It is a 1970. I went to a Wilwood set up and used the adjustable prop valve. I first used a master for my year of Nova with disc /Drum. The pedal was hard as a rock. That master has a 1 1/8" bore. Wilwood said that was my problem. I have drums on back but I used a master from a 68-72 corvette with 4 wheel disc brakes. it has a 1" bore. I did not instal residual valves to the rear I just figured I would try it and see how it did...it stops great. NO PROBLEMS AT ALL. this is just an eighth mile bracket car with a big block.

JMO

[prostreet1972]

I just put manual discs on the front of my 72 chevelle. I used a master cyl. from a 69 vette disc/drum with a summit prop. valve to the rear. These brakes are awesome, the pedal is just right...not too soft, not too hard. Also have hurst roll control up front.

I did most of my research on www.chevelles.com