I switch from a 83 to a 92 brake booster with the new proportioning block. the rear brakes are from a 94 Z they are the larger disc. from experimentation i found that no valve in there works best but the rubber cap blows off and fluid goes everywhere. how can i properly adjust this to get the correct brake pressure for my set up.

 

To be sure you need no valve I would lock the brakes and have a friend watch if and when the rears lock. If the rears lock before the fronts, you NEED a valve. Most likely you will need one.

The issue with fluid shooting out of the M/C is another issue. When hitting the brakes it is normal for a stream of fluid to hit the top cover, but they're shouldn't be any pressure to pop it off. Are the clips on the sides broken off?