Quadrajets were used as original equipment on many vehicles from 1965 to 1990. Over 100 million have been produced. 1966 Rochester Quadrajet used on 327 Chevrolet engine with manual transmission, no. 7026203 - number is on the blue 'bottle cap' visible on the throttle side. Design The QJet is a large 4 barrel carburetor that has a small primary side for fuel economy and good emissions and a large secondary side for good performance.