pimpilac
+1y
The E4ME is an electronic feedback carb for the computer it's 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. QJets have a maximum airflow of from 750-800 cfm. Because the secondary side of the Qjet opens according to the airflow requirements of the engine, the same basic carburetor size can be used on a large range of engine sizes. The basic 750 cfm QJet casting is used from 231 CID to over 400 CID - the big secondary air valves open only as the engine breathes. For example, on a mild 350 Chevy the air valve will never open all the way - because the motor can't use more than 600 cfm or so.
The beauty of the Q-Jet is that little has to be done to tune them up for improvements to performance mods. The Carb is able to adjust itself for minor ones.
Best thing you gan do for a Q-Jet is to overhaul it and make sure the air bleed off is correctly set. Make sure the power valve piston is clean and properly working and electrical connections are clean and working properly. All fault codes in the computer memory need to be corrected and cleared.
DO NOT adjust the secondaries so that when the throttle is open fully that the throttle plates are 90 deg to the venturi. It will reduce the performance.
Hope this help's if not i'll try again