Distribution Block,72 Swinger

Can somebody answer this >>>
SO if i converted my 1969 Dart Swinger front drum brakes to factory front kelsey hayes discs ( Manual brakes )... What should i use BLK 250 AND hold off valve ... OR Distribution block AND hold off valve ???
It seems that 68/69 Darts with front discs had a 2 piece front to rear brake line ... SO there has to be to brass junctions needed ...
It seems like when calling to order parts ... seller not sure what to install ???