An original equipment type proportioning valve (not the mickey mouse aftermarket type) has an isolator piston built in which is essential for the dual master cylinder to operate properly. When there is a pressure loss to one end of the system the piston moves to block off fluid flow to that line and preserve flow to the lines that can still contain pressure. Without the isolator piston the whole concept of the dual-circuit master cylinder is worthless. The valve you need to use will have an idiot light switch. Whether or not you choose to connect the light is up to you, but the valve needs to be there, no matter if the system is Huck or Bendix.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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