Well, that was not what I was expecting to see on the pedal box. But I'll agree with the GM master for the brakes and the clutch master looks like the one in my Studebaker
Definitely shouldn't be a problem at the parts store. Most of the Arntz / Bulter cars I have seen have the dual brake masters with a balance bar, so that's what I was envisioning...
On another note, did your rear suspension come that way when you bought the car? Very nice that you have all the latest upgrades (sway bar, strut rod kit, Aldan coil-overs) although someone goofed on the rear strut rod frame mount. It's upside-down and backwards; probably works fine but not as stiff as it could be. And I'd love to know where the differential stiffening plate (under the diff) came from; it's the lightweight version!
Jason