I have searched a ton on this and havn't been able to find the answer. So my truck is a 97 f150 with rear ABS, now to make things tricky I have swaped an 02 9.75 with disk into the truck and took the MC from the 02 as well. I am now getting rid of the vacuum brakes and switching to a hydroboost unit. Should I have a adjustable prop valve in the rear line or is it already built in somewhere between the new MC and my current abs unit? Thanks.