If economy is a major concern stick with the Q-Jet, get a quality reman from JET if you don't think you want to tackle rebuilding one. Otherwise I'd go with the 1400 Performer over the 1406, it is calibrated for fuel economy.
Originally Posted by curtis73
. chances are you don't need an adapter. Most spreadbore intakes are drilled with both carb bolt patterns. Pull the carb and see if the intake has 8 bolt holes. Putting a square on a spread intake is fine if that's the case. The problem comes when putting a spread carb on a square intake. The secondaries have to make such a radical transition to the plenum that it never works right, but no worries going from square carb to spread intake.
I've never seen a factory Chevy Q-Jet intake with both mounting patterns on it.