[Jeff Chambers]

Back to the original question. If there was a power valve in the secondaries, then the carb would be jetted squared up (or nearly so). With no PV in the secondaries the spread was jetted correctly to begin with. To go another 8 jets on the secondary would be overkill to say the least. Reading plugs isn't always as easy as people would believe and is not the best way to check the A/F. Take the car to your local dyno shop and have it checked with a wideband O2. On the PV, I've always gone by the rule of thumb of dividing the curb idle vacuum level by two and run that PV (15"-hg /2 = 7.5 PV). Like others have said, if you can put the car under light load when you check the curb idle vacuum level even better.