Proportioning Valve

I recently went to bbp disc brakes on the front of my 69 Dart. I ordered 74 Dart brakes from Rock Auto and new master cylinder for disc front/drum rear. I bled the brakes and had no leaks at the bleeders. Everything seemed good up til actually testing the brakes on a little brake check up/down my driveway. The brakes feel very very weak and sluggish. I have to drive my foot straight into the floor in order for them to fully engage. After a little inspection I noticed there was some brake fluid on the proportioning valve. This would be the stock proportioning valve for small bolt drums all around. Is there another proportioning valve I should be using? Should I drive the car a bit for a brakes/calipers to break in? Any thoughts on why they might be sluggish.

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