440 EFI fuel mileage

[Dreamcatcher]

I would like to hear fuel mileage numbers from anyone who has converted a 440 to fuel injection. And what unit your running. I see so many out there from edelbrock , Fitech , holley and others. I would like to know how they compare in ease of installation over all operation and fuel mileage. I am leaning towards Fitech for the 440 hp in my bird but really want to hear pro's and con's.
Thanks

 

[Big Sugar]

Well FiTech is on the list for me..but I switched out to a A518 transmission two years ago and I get a nice 17 mpg average with conservative driving..............................10 mpg when I drive it like I should.

 

[Dreamcatcher]

That is why I ask this question (and thanks for answering) I have a 440 hp in my S bird I love to drive it. But the only carb it seems to run good with is a comp. series carter and at best I am at 11 to 12 mpg. would drive the wheels off it at 17. Don't need preius numbers just something around 17 to 18. I know in the day 12 was the norm but with todays technology I would think it very possible with out full blown modern engine swap.

 

[Cranky]

Performance and fuel economy is a trade off no matter if you have EFI or a carb but generally, EFI is better in town because it's more efficient. A computer manages the engine better than most can with their right foot but you still need a certain amount of fuel to run the engine. You can usually tune an engine to make it get better economy but it's going to hurt performance. I increased the MPG on a 383 Challenger just by going to a 2.94 gear from 3.23's. In town numbers improved only 1MPG from 12 to 13 (didn't expect that) but highway went from 14 to 17. Usually, a lower ratio in the rear end helps the engine get the car moving easier than a higher does and in town numbers usually get better. I installed a 3.91 in a /6 Dart and my in town mileage went up quite a bit but the 3.91 was a bit much for highway economy with the much higher engine rpm.....

 

[dpstark2]

My 3.23's behind the 727 are showing instantaneous mileage of 15-18mpg at 65 mph. Practically speaking, it should be on the low end of that. In town didn't change much because I get in and out of the throttle too much. The cost of EFI buys a lot of gas...

 

[slepr1]

I'm not sure of the MPG but my buddy owns a 71 Demon 340 with a Holley 750 DP and I have a Edelbrock E-Street EFI in my 71 Cuda 440. We go for a cruise in both cars and use the same amount of gas and sometimes his uses more. Both have 3:55 gears.

I like the sump tank for the electric fuel pump in my system. No fuel tank mods needed.

 

[Dreamcatcher]

I already have the 271 gears in the bird. I just know that most engines run more efficient with EFI than with out. And if you don't drive a lot carbs are finicky at best. With my high gears my RPM's pretty much match what a newer car turns with overdrive. But she sure likes the gas. And I have talked to people who are getting better than 20 with a modern hemi and match my 440's hp or better. I know they have OD transmissions but like I said my engine speed is with in a few hundred RPM's of theirs with my gears. Of coarse weight is a factor too. But a 6.1 in a charger with that big trans. isn't much different than what I have. Like I said just curious as to what different EFI conversions are getting. I might run a new 5.7 in my charger but my bird isn't giving up its 440 hp motor any time soon lol.

 

[Sweet5ltr]

Until owners start installing Wide Band 02 sensors and monitor AFR readouts in their classic cars, carburetors will indefinitely fall short of modern fuel injection. Tuning is fairly simple once you have the ability to do it, 14.5 AFR idle & cruise, around 13.0 AFR WOT. This is exactly what a Dyno operator does to obtain peak power. Peak power is relatively identical (AFR wise) with gasoline applications, obviously forced induction has a different range for WOT. The kits are fairly reasonable, it's surprising they haven't caught on for N/A cars.

I got 14 MPG with my turbo 440 (MP .590 camshaft!!!), 4.10 gears, 29" DR's, and 4-speed @ 60-65 MPH. Nearly identical fuel economy with the correct turbo grind cam, 2.94's, and 727 automatic with 32* locked timing (try this cruising near off idle with 30" DR's). Stock was around 17 MPG with the 383, 4-speed, and 3.23 gears. Swapped to a lighter weight wheel and tire combination, also have a proper timing curve via MSD 6530. Hoping for 15-16 MPG on my next road trip.

 

[Bigal75]

Gas mileage with an old muscle car...interesting theory.

 

[watermelon]

i converted my 66 Coronet 440cu/727auto to the MSD Atomic EFI, electric fuel pump in the tank, and return-style fuel system. i have the 2.76 rear end.

unfortunately i did not pay attention to mpg before the conversion...still havent been paying attention to mpg. doesnt help that the throttle gets mashed all the time

 

[SlinktRR]

I think you will be disappointed with the conversion if all you are after is mpg. Well tuned carbs will do just as well.

 

[69 GTX]

Back in the day with my 383 RR with 3.23 750 Holley vac sec & dual plane intake. I got 16 on the highway but I had that carb tuned razor sharp. The art of tuning a carb is quickly becoming a thing of the past.

 

[Dennis H]

I can squeeze 18 highway 850 Demon with TKO gears. Not often. No vacuum advance.