71 vs 72 thermoquad

hi, the carbs will work as both use same intake manifold. the difference is in the secondary jet. the 71 sec jets were shorter as the body had longer casting to put jet near the floor. the72 and up, has a longer sec jet, commanly refered to as a solid fuel type.the casting was shortened to make then fit. both have 1 3/8 primary throttle bores. the 340 used the 1 3/8 bores. 71 through 73 . the intake 2100 has no EGR fittings in floor.