Proportioning valve question

This is from 67 FSM ( the proportion is close to 65%)

Screenshot_20231010-121951.png

69 FSM ( the proportion is closer to 75 %)
Screenshot_20231010-122649.png


73 the combo valve has the same spec as the pre 73 separate valves but the combo "metering" valve is a bit different in function

Though I don't think they were used on A bodies.

Screenshot_20231010-123154.png