Hi Eric: Yes the valve has 3 equi-spaced prongs. Further, the distance from the valve seating surface to the far side of these prongs is ~7 mm and the diameter of that portion of the valve that inserts into the booster is ~22 mm. The overall diameter of the valve body is 1 ½”. It takes a 3/8” I.D. hose.

Before we go any further, I like to ask a favor, which is for you to check the response characteristics of a new valve when going from higher manifold vacuum than booster vacuum to lower manifold vacuum to booster vacuum and vice versa. I suspect there is hysteresis or delay or something built in to prevent excessive valve rattling (which BTW is what we’re experiencing now) when the vacuum levels on both sides are ~ the same.

I tested the one currently in the car by alternately blowing and sucking (no rude comments please) on the hose barb, and the response time was pressure sensitive, but it seemed to me that it took an excessively large pressure differential to “turn the valve around”. I recognize that this isn’t very good science, since I’ve really no idea of the pressure/suction levels I’m generating with this technique.

Comments please. And price.

Thanks,
--
Barry -- 1967 122S 'Betty'