Vacuum Pressure and Potential Brake Issues

[greenweenie1969]

Hey all! I have a 383 stroker crate motor on my 1969 c20 2wd. I have upgraded to front and rear disc brakes from the original drum brakes. I was speaking with another customer of the same engine builder about our setups and he said he had issues with low vacuum pressure do to the larger cam they put in the engines. I spoke with the builder about this and they said it produces 16-19 psi. So I am wondering if that will be enough?

If it is not, what are some better options for master cylinder/booster setups? I planned on replacing the original anyways as this is a frame off so I want to get the proper setup.

Thanks.

[jessemthompson]

16-19 psi is enough for power brakes. If you’re still concerned though, you can always go with a hydroboost system. Aftermarket they are expensive, but you can piece your own together for a very reasonable price. The hydroboost creates a lot more pressure than power brakes as well.

[geezer#99]

You got some specs on your crate?
How much vacuum did the other customer have?
The engine builders numbers are pure speculation. All depends on motor tune, timing spot on, rings and valves seated, cam specs etc.
Normally minimum could be 14 hg.
Vacuum isn’t measured in psi.

[jimijam00]

Vacuum canister

[gmc684x4]

You can use a hydroboost brake setup
I am doing that with my c10 build use a hydroboost out of a 99 express van
From what i have read square body 1 ton trucks are the prefered to use in our trucks

[57taskforce]

I would hydroboost it regardless to be honest. It’s the single best thing I’ve done to my K20 to date. I can lock all four tires up on asphalt with little effort if I choose to. Obviously locked and sliding isn’t stopping faster but the assist is quite a bit stronger than my vacuum setup ever was. It also provides very nice pedal feel. The unit in my truck came from a 2009ish silverado 2500 with a 6.0. You see the install in the build thread for my K20, see my signature.

[Steeveedee]

It would be easier and cheaper to install a vacuum pump if the engine doesn't pull enough vacuum at idle. I'd personally use a properly sized manual master cylinder if it were mine.

[gmc684x4]

The op built a done up 383
I doubt he wants to take his truck back to the 60s with manual brakes and manual stearing approach

Hydroboost are expensive if you buy it as a kit from lmc lots of late model salvage options

[Steeveedee]

Originally Posted by gmc684x4

The op built a done up 383
I doubt he wants to take his truck back to the 60s with manual brakes and manual stearing approach

Hydroboost are expensive if you buy it as a kit from lmc lots of late model salvage options

True. I should just let people drop their money without other considerations.