Earlier I posted I worked at a GM dealership. Did a LOT of carbs... Qjets are comparable to EFI for mileage and off roadability. Closest you'll ever get to the same performance.
I also posted earlier that EFI was not developed for mileage increase. It was designed for emissions. With that said, once again I have a story that relates.
Johnnyb, If you get 20% better mileage with efi than with a carb then you need to rebuild your carb.
9 of us drove to The Con from PNW. Slept on the grass in rest stops all the way there and back. 4 were fuel injected. 2 were Exploder motors (almost new). Rest were carb'd.
At every fuel stop and I mean every fuel stop, my 351W (18% larger cubes) got better mileage than EVERY other Bronco. We all drove together, we all had 2 guys in each rig and loaded for 10 days of adventure!! We all filled up at the same stations (except a couple times) and the EFI guys and myself checked our mileage every time because they were all trying to beat my mileage #'s. lol
All my numbers were written on my dash. Left them there for years till I rewired. lol I have pics somewhere. I averaged 13.5 to 14.3mpg most of the way. Got less on the trail but...
I also got better mileage on the trail than anybody. EVERYBODY there couldn't believe that my larger engine with a carb got better mileage than the new, cool, efi powered Exploder motors. This was in the early 2000's.
My 418 with a Qjet got the same mileage as my 418 with the EFI guys tune. Started quicker, ran better at 7,000ft but cost a lot more than EFI and was/is a LOT less complicated. Heck, my wife held a water can full of gas out the window with a syphon hose stuck in it, across the hood, thru the slotted vents and connected to the fuel inlet. We towed our trailer 40 miles to the nearest truck stop/exit.
Sometimes simple is really important.
Fact.