I used a jeep disk/drum combo valve on my 65 retrofit. Same setup. Front small reservoir plums right to rear side of block: back brake supply line, large rear reservoir plumbs into front side: 2 front drum feeds. Combo valve is supposed to provide: proper front bias, distrubution, and I think there is even a grounding contact on top for a brake warning lamp. Top 1/2-20 is front feed in and top 7/16-24 is rear feed in. 3/8-24 outs are front disk lines (2) and bottom
This doesnt apply to Inline Tube Co's 65 dual line kit and proportioning block. What you get from ITC is what I posted and the fittings on block you pictured would be all wrong sizes, requiring a complete retube of whole car.
