Will a 9" single diaphram booster provide enough boost for a 67 Firebird with 4 wheel disc brakes? Also do I need a special master cylinder or will one for front wheel discs rear drums work? I understand I need a special porportioning valve which I have.

Will a 9" single diaphram booster provide enough boost for a 67 Firebird with 4 wheel disc brakes? Also do I need a special master cylinder or will one for front wheel discs rear drums work? I understand I need a special porportioning valve which I have.

Probably not.
Yes.
Yes, you will.

We did a 67 Mustang last week with S10 calipers and manual master; worked nice- stopped well and VERY easy to modulate stopping power.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by 455earlybird:
Will a 9" single diaphram booster provide enough boost for a 67 Firebird with 4 wheel disc brakes? Also do I need a special master cylinder or will one for front wheel discs rear drums work? I understand I need a special porportioning valve which I have. </div></BLOCKQUOTE>

If you are using disc all around you should use a 4 wheel disk master cylinder and combination valve. I think th 9" will do the trick but you might want to let someone else chime in on this.

Here is my setup on my 67 convert for brakes

Front - 69 Chevelle single piston
Rear - 78 Seville with parking brakes. These are same size as the single piston on the front.

Hyrdo boost/master cylinder/combo valve from 76 Eldorado. I'm using the hydroboost because my cam probably won't draw enough vacuum. This master cylinder matches the caliper size I am using also.

I'll probably need to make custom length rear parking brake cables. I'll find out in a few weeks when I finally get my brakes fully installed.

While the car is still in progress I have talked to others with this setup and it works GREAT from their reactions.

But bottom line master cylinder and prop/combo valve need to match they type of brakes you are using.