i have a 71 Chevy pickup with a 68 327 in it. i just got it built to about 500 hp. when i first got it done i had no brakes. i installed a vacuum canister. it is better but if i get in stop and go traffic the brakes fade quickly. is there anything else i can do to get more brakes.

i have a 71 Chevy pickup with a 68 327 in it. i just got it built to about 500 hp. when i first got it done i had no brakes. i installed a vacuum canister. it is better but if i get in stop and go traffic the brakes fade quickly. is there anything else i can do to get more brakes.
There are electrically opeated vacuum assist pumps on the market

You want the most vacuum to occur while you are idling -- the timing and idle mixture should be adjusted so that vacuum is highest at this time.

Obviously, that 500hp cam you have in there does not help, but I like it :)

The choice would be to either swap to a cam with (a lot) less duration, or drop the power assist brakes.

Guess what I would do?

The other choice would be a hydro-boost power brake system.

An easy cure for a friend's car was to install a mechanical vacuum pump.
The early Ford F250 Diesel trucks all had fan belt operated vac'pumps. I think the one we used came from a late '80s Cadillac Sedan Deville.
The rebuilt pumps usually cost under $100, you'll just have to figure a location to mount it.
Hydro units do work great. A vacuum pump would be easier to install and cheaper in price.

The dilemma then becomes how much horsepower do we lose by:

Stepping down the cam?

Driving the alternator harder to run an electric pump?

Driving a belt driven vacuuim pump?

Options are what makes this hobby so much fun :)

I have a hydro boost equipped car. It runs off the power steering box and normally are found on diesel equipped GM cars. Some wagons like mine came with it, and personally I'd never have another one. I had to replace it, the unit went for about $160 rebuilt and cost another $275 to install it.

I'm sure some GM trucks came with them, you just have to make sure you have the right steering box to tap into. It also takes a different master cylinder. They do run a little noisier than power brakes, but stop well and might be what you need to do.

Bob

thanks for all the feedback. i found a manuel kit that includes the master cylinder and proportioning valve for $160. I think i will go with that.