power valve plugs

[GregM784]

Power valves are needed for the intermediate circuit of a carburator. The down sides are they are not always predictable, and they can leak (blow out, rip, etc). If you stage at full throttle (two step or full stall on the converter) and do not drive the car around town, you have no need for the inter. circuit. With plugs in both sides, your jetting becomes square. your jetting becomes more precise.

[Ron Gribble]

I pretty much agree,
But I have seen many cases where a car cant get "on the converter" unless it has a power valve. With a clutch, I never run one. If you do run one with a converter play with different vacuum settings. It can make a big difference how quickly it stalls. If you dont need it, dont run it. Its one more thing to go wrong.
My 2 cents
Ron