[turbovanman]

I have a 75 B250 with a raised roof I put on, it weighs 5000 lbs, I weighed it at the scales. It came with a 318, auto, shit Carter 2 bbl, no egr and never got better than 12, even with headers and I added 12 inches to the collectors which made a big difference in towing grunt, dual exhaust, ram air-power went up but fuel stayed the same. With 3.3 rear gears, it still screams at 3500 rpm at 65mph. I tow with it and even that never changed the MPG. Switched to a 4 barrel and Edelbrock dual plane manifold, worse due to the Holley being a pig, installed an Edelbrock 600 cfm, worst of 9 and best of 12. Installed Qjet from a Chevy engine, could only get 1/2 throttle dueto linkage isues and got 14. Engine is tired so install a .030 360, real X heads with 2.02 valves, minor port work, RV cam, rejetted Edelbrock and guess what, 10 friggin MPG. worst of 8-9 towing a heavy bike trailer. Dynoed at 420 ft/lbs of torque though. Tried Demon, shit btw and finally running a Dodge Qjet, now average 10-12 again.