Not something I usually concern myself with in this hobby doing local cruise nights and short drives but we're taking our first long (about 2500mi) round trip this year. I've swapped the 3:55's for 2:94's, It'll get fresh oil and filter, fresh set of plugs and check tire pressures before leaving. The few day trips I've done so far are giviving me 14mpg cruising close to 60mph in my 340/6 a-body. Can anybody give me approximate numbers that they're getting, if you keep track of such things. Please include body type, drivetrain and rear gears so we have a fighting chance at keeping this all straight😁! Also any suggestions on squeezing better mileage out of a six pack would be much appreciated.

Get an Air/fuel reader in the exhaust and tune your distributor to go in 40's during cruise.

What do you have for a torque converter and camshast.

This was from 20+ years ago, before 10% ethanol gas...

70 Super Bee
-orginal 440-6 gone, replaced with used '69 std 440 LP, 440-6 int and exh manifolds swapped over
-orginal 727 trans & 3.23 SG
-1 jet size larger on center carb
-int and mech timing 38*, vac adv unknown, dist is MP electronic

Trip...
250 miles
80% hwy @70, 20% city
result, 16 MPG

One of the reasons I advocated having an OD transmission for the last decade and a half, sure gas is "cheap" for now (not really)but who knows what the future holds...

I'd see 14-16 MPG cruising 70-80 MPH in a 71 B body with a 472 HEMI with a 6 bbl induction, 4:10 gears running a TKO 600 5spd with .64 OD on long hauls

My 70 Charger Daytona 440/6 450hp 4:10 dana, TKO600 5spd .64 OD would get upwards of 22 MPG cruising 80+ MPH on HotRod Power Tours and other cross country driving events

On the streets however I could destroy those MPG figures into the single digits if I had my foot in it, so tune all you want, drive prudently, granny shift, etc, etc, you won't see any drastic results until you take advantage of some mechanical/mathematical gear/RPM reduction

Pump up those tires to 50lbs. and slow the hell down! Throw a bag of ice on the intake??? I'm thinking that's pretty good, you could try squeezing one more with timing and whatnot. Tires at least 40lbs. will help a little.

I think 14 MPG is decent.

I ran a '70E about 4,000 miles in 10 days a couple of years ago. From IL to CA and back over the Rockies. 14 MPG running 75-80 ish. Engine is a 496B with warm cam. EFI, .81 OD TKO, 3.23 rear and ~25" tires. At light cruise running around 50 degrees advance and a little lean on the AF. One tuning challenge was when to dial back advance and richen the mixture for moderate acceleration w/o rattle. WOT is pretty easy to tune. I would likely have gotten 15+ MPG with taller OD which the engine could eaisly handle at cruising speed... but like the shorter OD as a top end track gear.

My understanding, the 6 pack can do quite well with careful tuning of the center carb and plenty of vacuum advance (50+ degrees?). Just a little easier to get there with EFI. Also, EFI handles altitude, temp and fuel changes w/o penalty which matters a lot in the mountains.

This is an interesting topic. We have an 81 Imperial with the 904. It has 139K original on drivetrain. So far everything is holding up well. However given the mileage, the thought occurred to me that if the trans ever needs an overhaul I have thought about dropping in a 4-speed OD from a truck from the late 80s' early 90's before they put in the electronic controls. I cannot imagine it would be technically difficult.

528 Hemi all iron 10:1 CR, dual AFB's with progressive linkage, stock intake, stock exhaust manifolds, very small cam (270 advertised), 30deg timing, 727auto, 3.23 gears, electric fans, non power steer, non power brakes, 26" tires @ 32psi, in 70 b-body.

13 mpg with pump-93

My Challenger 360, 224@.050 cam TTI headers and 2.5 exh,650 Holley DP (leaned 2 jet sizes),LD340,4 speed, 2.76 gear for a trip out west. 18mpg
Doug

Bone stock 340 Swinger with 383 AVS, 3.23's 14" tires, 18 mpg on highway. Swapping a single 4 for the road trip would be the biggest mpg boost you could make.

526 wedge, 3.73's 4600lbs. 14.6 on the 3 her ride to Carlisle.
Trying to keep it around 3000rpm.

Magnum, pretty mild stuff, 2200 stall with a 286XE cam. My plan is also to run the black springs in the outers to try to stay just on the center carb, and of course keep my foot out of the loud pedal

Stock 74 Duster360, 727 and 2.45:1 rear gear with 235/60/14 tires . . . ran 70mph all day long - 22mpg !!

Stock 76 Road Runner, 318 with factory 4spd OD, not sure rear gear, same tire as Duster360, 70mph all day long - 22mpg.

Stock 70 300Hurst (Ragtop), 440, 727, 3.23:1 rear gear, 50 - 80mph (didn't seem to matter the speed), 16mpg all day long . . .

Cheers,

Canadian or US gallons?

US gallon