Ya need one like this.About $20.00 and last forever.
Hang on and I will see if I can get ya a link.

 

hmm never seen anything like that. just curious how do you know that the brake booster is not the correct way to go bout this? like what type of motor setup do you have on your car?

 

http://www.eskoindustries.com/eps/chk.php


One like this the proper size would be nice just unscrew the fitting in the manifold and put this in it's place and hook the hose back up.

 

Well it's plastic and not designed for the heat or the pressure.
Don't care what ya use I prefer metal for the longevity.

I have my own shop and do this for customers. I build engines and that's mostly it.
I know because I have tried it.

Well my shop car has a n/a 383 in a '94 putting out 690+FWHP on pump gas and is driven on the street.Still has the AC and all the factory equipment.
Bet that's close to what ya put out with a blower.

 

so the little round thing that looks like a not on the top of that npt nipple is a check valve?