Proportional Valve ??

[ck5566]

How do you tell the difference of the proportional valve between the two systems disc or drum and or disc/drum and if ether one is being used for power brakes or manual brakes? I am asking this because the PO's installed newer spindles (92) with disc brakes on front. It is still a manual brake system and with what is installed it doesn't seem to brake real good. I know manual system isn't the greatest but it still doesn't seem right. I'll insert some pic's for I D purposes. thanks