Is it possible to switch out my therma quad to a smaller carb ?
yes. Remember the thermo quad is a great carb, just build it right. It is a "demend" carb, but try a Holley 4360 Econmaster. It is a direct replacment for the big thermoquad and the mileage should increase with no real loss of power. I did this and kept the "lean burn ignition and it still ran great. Not for strip use, but no problems on a 1978 LeBaron wagon, it certainly slow it down but road milage went up nearly 4 mpg.
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