Jetting a carburetor is one of the few "black arts" in the automotive world that is still a mystery to most racers and tuners. Most tuners still look at the spark plug, the exhaust port, and the first ...

Holley has always offered vacuum-secondary performance carburetors in two versions--4150 models with replaceable jets in the secondaries, and 4160 models with a metering plate and no replaceable jets.

Factory production vehicles haven't rolled off the Big Three's assemblyline with new carburetors since the '80s, but it's still the mostpopular choice of induction among car crafters. Don't get us ...