Grassroots Motorsports

Register Log in to GRM
- Community

Birthdays
Recently on the Classic Motorsports forums

Subscribe get a full year for only $23.95 Sample Free Test Drive—no strings attached

Login to post Forums » Grassroots Motorsports » 19.5 mpg and I can tow two ridgelines on the back of it.

June 1, 2010 12:16 a.m. CaptainSpaulding New Reader

Just got done with the first long distance drive in the new truck. 1989 Ford F250 4wd C6 3spd auto 4.10s and the all mighty 7.3 idi international diesel.

Took a 180 mile trip and averaged 19.5 cruising 65 mph with about 1k lbs of junk in the back.

I thought that was pretty good for the old beater. Only mods are a new water pump and a 1/16 of a turn on the fuel pump. The truck was spinning 2800 the whole way and redline is 3k.

Cant wait to add some boost and a new ip and squirters.

Paid 1200 for the old girl a few months back. Still needs U joints and some front end work.
June 1, 2010 4:08 a.m. Jay Dork

They mated an engine that redlines at 3k to a 3-speed? Ouch.

Looks like a hell of a truck for $1200 though. I'd black out that grille and front bumper.
June 1, 2010 5:40 a.m. foxtrapper SuperDork

C6 and 4wd and you're getting 19 on the highway? That's downright remarkable.
June 1, 2010 5:44 a.m. 914Driver SuperDork

What??!!!! I get that kind of milage in my 2.3 Ranger.

Dan
June 1, 2010 5:48 a.m. DrBoost Dork

I'd get 23 on the highway in my Dodge with the king of all diesels under the hood. No matter how loaded I don't think I ever saw less than 17 mpg. It appears you've discovered what some of us here know, you just can't beat a nice old truck with a diesel for economy and pulling power. Nice find!
June 1, 2010 8:10 a.m. chknhwk Reader

Win.
June 1, 2010 9:41 a.m. car39 Reader

Or you could drive my 04 250 crew cab gas motor and get 8.8 mpg with or without a 20 foot enclosed trailer. I meet a lot of nice people at the gas station.
June 1, 2010 9:57 a.m. alfadriver Dork

Is there a 4 or 5 speed manual that can be bolted to the rear of that engine?

Maybe I need to suggest an engine transplant for our Bville tow rig...

E-
June 1, 2010 10:27 a.m. dean1484 Dork

Two speed rear end.
June 1, 2010 10:40 a.m. Giant Purple Snorklewacker SuperDork

Nice find. I have a new-to-me 6.6L Chevy oil burner w/ a 5sp and get 19/23 unloaded and 16 pulling an 8500lb box at 75mph. Who knew, right? I'll never buy anything else but diesel for mundane type driving or work.

I still can't break the grip of gas for "fun" cars though. There is no way I can enjoy the sound of a diesel and there is just no substitute for the sound/vibration high rpm wailing of NA gas engines (including rotaries).
June 1, 2010 10:58 a.m. SillyImportRacer Reader

In reply to car39:

Wow, I thought 10mpg hwy was bad for my 79 K10.
June 1, 2010 12:00 p.m. a401cj New Reader

need a gear swap to 3.55. If 2800 is 65 mph you can't even run the speed limit in some states. Turnin up the boost ain't gonna help either
June 1, 2010 12:44 p.m. mad_machine SuperDork

he might be able to hit 70mph... it all depends on what part of the country.. here in the NE... 65 is the limit. I used to be able to coax an Isuzu box truck to 3100rpms and 75mph
June 1, 2010 2:05 p.m. CaptainSpaulding New Reader

Alfadriver.

You could get them with a 4spd in the early years and later a 5spd zf trans and a 4 speed auto. The C6 is bulletproof and the later over drive trans have problems.
June 1, 2010 2:08 p.m. CaptainSpaulding New Reader

a401cj

I am ok with 65mph. I get there when I get there. With the 4.10s she pulls the 7% grades at 8k feet just fine and up in the hills the speed limit is usually 55.

Also dont forget that when the truck was built the average speed limit and in some cases federaly mandated speed limit was 55.

No boost to turn up its N/A. Thinking of adding boost. A non wastegated turbo to keep the mileage and power up. It doesnt need that extra power untill you put a load on it.
June 1, 2010 2:15 p.m. GameboyRMH SuperDork

Wow, not bad for a big ol' truck with a 3-speed.
June 1, 2010 8:13 p.m. 924guy Dork

Or you could drive my 04 250 crew cab gas motor and get 8.8 mpg with or without a 20 foot enclosed trailer. I meet a lot of nice people at the gas station.

my last pick up got 6mpg , highway, unladen... come to think of it, laden, unladen, didnt make a difference, always 6mpg, ford 460's go figure... but i did love that beasty F350 crew cab dually, and it was fast as berkeley...

the next one will be a diesel...
June 2, 2010 7:11 a.m. redzcstandardhatch Reader

i LOVE our 7.3s. we've got three at work . one has 450k on it, never had to change anything but 3 sensors, 2 waterpumps, and 3 alternators. original turbo, engine, trans, rear,etc.

another i took to florida for challenge with our crx, a FULL load, 3 dudes, big-ish 1car trailer, a moped, etc, and got 20-21 MPG the whole trip (3.83 rear, 5 speed auto)

i WANT an old f250 like that.
June 2, 2010 7:18 a.m. bravenrace Dork

car39 wrote:

Or you could drive my 04 250 crew cab gas motor and get 8.8 mpg with or without a 20 foot enclosed trailer. I meet a lot of nice people at the gas station.

And you've figured out how to defy physics!!!!
June 2, 2010 7:19 a.m. bravenrace Dork

SillyImportRacer wrote:

In reply to car39:

Wow, I thought 10mpg hwy was bad for my 79 K10.

The best I get with my '78 C-30 is 8 mpg. The best.
June 2, 2010 12:30 p.m. a401cj New Reader

bravenrace wrote:

SillyImportRacer wrote:

In reply to car39:

Wow, I thought 10mpg hwy was bad for my 79 K10.

The best I get with my '78 C-30 is 8 mpg. The best.

If that's with a 454 then not too bad. My neighbor's got 4!
June 3, 2010 8:38 a.m. bravenrace Dork

In reply to a401cj:

Yeah, it's a 454. I've had a few of them, and some got as high as 15 mpg. Mine is much worse because of a 4.56 rearend. In my experience, 4 mpg means somethings wrong with it. I only say that because mine is a crew cab dually with a lot of heavy equipment on it, so I don't know what c-30 would get any worse mileage. Still, I prefer it to any diesel, since I've towed 14k lbs up mountains with it, the fuel is cheaper and I have a fraction into it then I would a comparable diesel. Plus I don't have to put up with all that noise.
June 3, 2010 8:50 a.m. Woody SuperDork

dean1484 wrote:

Two speed rear end.

Does anybody still make them?

You'll need to log in to post.