power brake vac

hi,
1975 b-body 400 race cam no specs yet, (drag race no street use) anybody run power brakes? hard pedal? switch to manual??
thanks
gary

Cam specs are somewhat irrelevant.

How much vacuum you have is, I've heard 17"/hg minimum.

If you have less than that there are things that can be done. Adding a vacuum pump is one. Going with manual brakes is another.

Since all my rides are manual brake setups it's not really an issue for me.

then there is the question of a single diaphragm or a dual diaphragm booster, and the booster size.
disc brakes usually use a dual diaphragm booster, while drums use a single one, but if enough vacuum is produced with a pump, maybe a single unit booster would work ?

This right there is a great point!

I have a dual-chamber booster on my Dippy coupe, the hydraulic flat tappet cam only pulls about 7" of vac, and it's dipped lower, right down to 5" at idle numerous times (mostly when I was tuning and trying a few things here and there), point being: my brakes have NEVER gone away!

This is with discs up front and drums at the back.

Thanks I'll try it as is , if I have a issue I'll add a pump

Before adding a pump you can try this...
https://www.summitracing.com/parts/...PsIGI8AIVDpezCh0zawk8EAQYAiABEgJzzfD_BwE

The booster is one big assed vacuum reservoir and neither helps if you don't have enough vacuum to begin with,

The idea behind the reservoir is that it will store the additional higher vacuum achieved while cruising at higher RPMs via a check valve. That higher vacuum will then be available at lower RPM's / vacuum. Might work in a marginal situation but I have had little success on customers cars so the pump gets my vote. I believe the reservoirs are more of a snake oil / band aid approach. but they are good at doing what they are marketed for, getting money from your wallet to the suppliers / manufacturers