Correct Proportioning Valve?

The attached photo is similar the valve that came off my car, is it the correct one I need for my application? I have front disc (73+) and rear drum. In doing some research, this valve has an ID # PVM70. All replacement versions look blocky and nothing like it and I am having a hard time finding any info on the valve itself. Are adjustable valves worth the investment?

I am thinking of all disc one day, but not today. I am still fixing things the previous owner had done to my 67 cuda and I want to make sure I am making sound upgrades. Thanks for any ideas.