'96 F150 with m5od, 3.55 gears, stock size tires. I put in a K&N drop in filter, 2.5" exhaust with Flowmaster, and a thorough tune-up. Its lost a lot of compression and burns a little oil now but I can still get 15-17mpg with mixed city/highway(I go 75 to 80mph on the highway). I do have heavier load tires which are inflated to max pressure of 45psi and 55psi. I expect to get it to 20mpg when I swap in the fresh 300 with a mild port, polish, and low dollar mods.

I know aerodynamics is the huge factor in these trucks. How they sit(rake, level), the bumper or valance, topper/toneau or open bed, ect. On a '94(5.0, auto 2wd) I had, I did a lot of different things with it. I could get better mileage on the freeway with a topper, but lost city mileage. The tonneau was a good compromise between the two. With just a tool box in the front of the bed, I noticed a small improvement. When I took the plastic valance off the front bumper, I lost mileage. On a '95 std. cab/short bed(5.0, 5-speed, 4x4), I found how stance affects them greatly. It came with a 4" rake(front sat 4" lower than rear). After I lowered the rear and raised the front a hair(sat level), I started getting unbelievable numbers. I went from 15 to getting over 20mpg.

Thats my experience.

 

When my 83 was stock: 1bbl 4spd Granny trans, 235/75/15's 3.08 gears. It'd pull an average of 12/14 around town if I babied it, and just about 20 on the interstate.

I'm hoping my new build will add a little performance go along with the above mileage. I've built a new 300, 600cfm 4bbl, Clifford "C" manifold, "tuned" distributor w/advance kit, EFI exhaust manis, AOD, and 3.50 rear gears. In town mileage I expect to improve a little bit, though I'm not so sure where I'll be on the highway mileage side. Also got some electric fans to figger out how to install once I'm done with breaking the engine in.

Can't wait for it to get back from the trans shop...

 

Original setup:

1bbl, 4spd w/OD, 215 75R15 tires, 3.00. 16 in town, 21 freeway (65mph). 17 (75mph).

New setup

4bbl Holley 390. Same Trans and rear. 31x10.5" tires. 13 town, 16 freeway. Hoping to bring that up still.



Bronco #2
4bbl Holley 600. 4spd/granny. 31x10.5" tires. 3.55. 14 town. Haven't taken it on the freeway yet, so I'm still curious. Sure seems to be a sipper though, even with the 600.

 

You bronco guys ... 3.00 rear ends AND overdrive!! You're killing me. I'm starting to think that the 15-16 mpg average on my trip with the Autolite 4100 was pretty darn good, considering my 3.31 rear, lack of O.D., AND the extra weight!!

I got to hijack the thread a bit here, AB. I spoke to the guy who literally wrote the book on QJ's today. Interesting. He mentioned that the Edelbrock is a copy of the Carter AFB which was abandoned in '67 because it would not pass emissions stardards.

 

I'd always heard that the Edelbrock was just a Carter in disguise. I didn't know that they were all pretty much descended from the old AFB. Learning something new every day!

 

My 300 with an Edelbrock 500cfm passed emissions testing three times with no worries. I just used a wideband A/F meter to dial it in. No longer a concern now that the Bronco turned 25 years old, though.

I've never done mpg calculations, mostly because I don't drive the Bronco all that much and usually don't fill the tank when I get gas.

 

--Stock 67 with 1bbl, and points, 435(4 speen man.), 3.50 gears on stock tires:11mpg tank avg.
--modded version; edel 500 carb, offyC intake, Hedman headder, Duraspark with 2 light springs, initial timing 14* and total timing 42*, stock coil, Summit 8mm wires, Summit ign control box, 274* cam(224* @.050), GM 292 rockers(makes .518 lift), same tires & gears: 10-12mpg.
--Soon to try some 2.75 gears for a 600 mile trip to Oregon next month. I'll be real happy if I get 15 on the highway.

 

The point is: there are two very diff. set of standards for the manufacturer and for the guy on the street.

 

87 F150 4x2, stock size tires, EFI 300, 4 speed manual with OD (not granny low equipped), freshly tuned/oil changed, 186k miles, around 16 MPG mixed driving And 70-75 on the freeway...thought it wasn't doing so great but reading over the rest I guess she ain't doing so bad!

 

Mine is a 82 F100 with a manual O/D trans with 2.75 rear gears. The motor has headers with offenhauser dp intake with holley 390 carb. The last time I checked it it got 18.5 on the highway. I've never checked in town due to most of my driving is on the highway. I've put smaller jets in the carb and have not checked the mileage since. My speedometer stopped working so I'm not sure i could check it accurately. I think I get a little better than before.

 

1985 f150 2wd with a 4 speed O/D with granny low (i believe) and 3.08 rear gears (says this on the tag) stock everything but has a 3" body lift with 33x12.5x15 tires. I calculated from the odometer and got 12-14MPG 70% highway 30% city. I don't think the odometer is right since the tires are a lot bigger than stock. I have to calculate it from the GPS on my phone next and see how far off it is.

 

shoot, I figure with a 2.75 rear gear you'd be netting 20+ on the freeway! I kinda envy you tall geared guys when I'm on a long trip but not when I'm pulling or hauling a heavy load...although hell, I bet you can still work the stew out of your truck with those highway gears! gotta love the 300!

 

I agree. I notice the improved mpg on all the highway-geared trucks. I mean 2.75 rears ... with over-drive!! If I converted to a ZF, in over-drive I would be getting what you have in normal fourth gear.

 

I have an 86 with a rebuilt 300 (about 500 miles), 4sp OD, 2.47 rearend, Edelbrock 500, Offenhauser DP intake, EFI exhaust, 255/70/15 tires.

I get 16-18 in a mix of city/hwy. Depends on keeping my foot out of it.

With my 2.47 rearend I'm really surprised at the acceleration. Much better than I thought. My mpg's probably would be better if I used the 390 Holley but I like the power I get with the 500cfm.

 

nolan, you have a gorgeous truck BTW