We will need a picture of you you got in the mail. Generally, the MC to the top of the dist block-rear brakes to the rear of the block, front brakes to the front. Line coming from the rear brakes goes on the bottom rear of the block, line coming from the pass side front wheel goes bottom front, drv side front goes in the front going straight into the block (horizontal)-generally...so, it says combo porportioning/distribution-does that mean it has a cylindrical part bracketed to it at an angle? THat would be an original disk/drum dist block. If thats what you have, and it's in pieces, you can determine how fluid would flow through the block with air (under pressure of course). As long as the porportioning valve is between the MC and the rear brake line, it should work as designed. Post a picture when you get a chance.