I WOULD NOT remove the proportioning valve.... you most likely need that -- and at the very least -- need to understand WHY you don't have good brakes before doing something like that.
You do need to do as suggested and check the vacuum - at the take off port for the brake booster.... at the engine. Or if you have a small vacuum gauge hose - at one of the other ports.
If you don't know how to do this - or don't have a gauge - it's a very simple (therefore should be super inexpensive) to have a shop do it for you.
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After you do that -- check the brake pedal ratio....
Here's a link to show you what that is:
http://techtalk.mpbrakes.com/how-to-...ng-pedal-ratio
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Next --- open the master cylinder -- tell us if there is a larger volume between the two reservoirs.... the larger (if there is a difference) needs to serve the FRONT brakes -- and the smaller (if there is a difference) needs to go to the rear. You can simply follow the lines to find if they go to the front or to the back.
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Did you BED the brakes after the installation?? Do you know what this means??