67-79 F250 with modern engine swap is 15+ mpg possible?

[Clutch]

And by the way...gas mileage and chevy crate motors should not be discussed together...:ylsmoke:

Ha!

Oh, I have been reading on some of the resto-mod forums, guys are getting mid 20's in their Chevelles....might be internet lore though.

Couple years ago I had a '76 crew almost on the flat bed for $800, engine was seized, tranny shot...but no major rust....they couldn't find the title...the owner had no interest in doing a bonded title.

I have seen the the fords mounted on Dodge Cummings. I would stick to putting a motor, transmission and wiring harness from a modern Ford truck. Buy a whole salvage truck for parts. It is a lot of work.

That could work too...not sure if I can get the tranny I want.

At high speed the issue is probably more aerodynamics instead of weight.

A modern truck is heavy, back in the 70's there was very little wiring, almost no sound damping material and the sound system weighed 2 pounds including the one speaker in the dash. Now with everything being whisper quiet, and miles of electrical wiring they are crazy heavy. The weight impacts fuel usage on acceleration etc. Aerodynamics impact once everything is moving and the energy to keep it moving.

Super quick glance, heaviest of the 70's era Ford F350 crew 8' bed was about 4865 lbs. Assume the F250 Crew 6.5' bed be in the low-mid 4000 pound range.

2014 F150 Crew is around 5350 lbs.

 

[njtacoma]

Super quick glance, heaviest of the 70's era Ford F350 crew 8' bed was about 4865 lbs. Assume the F250 Crew 6.5' bed be in the low-mid 4000 pound range.

2014 F150 Crew is around 5350 lbs.

Exactly my point, so although the weight will be lower, the aerodynamics are probably a bigger issue at highway speeds then the actual weight.
I hope you succeed because I have my eye on an IH Travelette (crew cab long bed) and would love to be able to talk my wife into the project under the guise of getting 15 mpg!

 

[Clutch]

Exactly my point, so although the weight will be lower, the aerodynamics are probably a bigger issue at highway speeds then the actual weight.
I hope you succeed because I have my eye on an IH Travelette (crew cab long bed) and would love to be able to talk my wife into the project under the guise of getting 15 mpg!

Who wants to pound out mile after mile of highway? Stick to the back roads...I think 15 mpg is possible.

Looks like this one has the coil sprung front axle off a 150. About the ride I height I want.

 

[1leglance]

I am looking at topping my carbed chevy engine off with fuel injection (TBI) and I fully expect 15mpg in my 70 suburban....but I like going 60-65 mph

Those 70's crew cab Fords are really nice and a great choice and I think with a Chevy crate motor (best deal in crate fuel injected setup) and a soft throttle foot with a manual trans you will get 15mpg.

With sound deadening and insulation my wife is very happy with how quiet my burb is inside, best of both worlds as it is a 70 burb that will be an 87 burb under the body.

 

[Clutch]

I am looking at topping my carbed chevy engine off with fuel injection (TBI) and I fully expect 15mpg in my 70 suburban....but I like going 60-65 mph

Those 70's crew cab Fords are really nice and a great choice and I think with a Chevy crate motor (best deal in crate fuel injected setup) and a soft throttle foot with a manual trans you will get 15mpg.

With sound deadening and insulation my wife is very happy with how quiet my burb is inside, best of both worlds as it is a 70 burb that will be an 87 burb under the body.

That sounds cool Lance.

I drive like an old man...my Taco (Which I am keeping) I generally average 17-18 with mixed driving. I think that is horrible for how small those things are. That said... I could live with 15. Heck, the Tundras get horrible mileage...what got me thinking...if I am going to spend that kind of money and get "ok" mileage...it might as well be cool. Tundras are nice...but kinda vanilla.

 

[RedF]

Keeping a lower average highway speed in mind, getting respectable fuel economy from an older truck should be pretty easy if you make smart choices with a modern drivetrain. An engine optimized for low RPM torque, an overdrive transmission, and gearing matched to tire size will be the main points to concentrate on.

Adding sound deadening and creature comforts will ensure you enjoy the drive.

Those old Fords are beautiful trucks!

 

[Clutch]

Keeping a lower average highway speed in mind, getting respectable fuel economy from an older truck should be pretty easy if you make smart choices with a modern drivetrain. An engine optimized for low RPM torque, an overdrive transmission, and gearing matched to tire size will be the main points to concentrate on.

Adding sound deadening and creature comforts will ensure you enjoy the drive.

Those old Fords are beautiful trucks!

Eco-Boost has 420 ft/lbs at 2500 rpm...



Not exactly what I had in mind...just want the drivetrain, but an idea. I think he ruins the interior, since that is some of the charm of the old trucks.

 

[RoyJ]

Keeping a lower average highway speed in mind, getting respectable fuel economy from an older truck should be pretty easy if you make smart choices with a modern drivetrain. An engine optimized for low RPM torque, an overdrive transmission, and gearing matched to tire size will be the main points to concentrate on.

Couldn't have said it better: lower hwy speeds + lower engine speeds are the trick to mpg.

Modern engines with variable valve timing, like the Gen V smallblocks, or Hemi, can run happily as low as 1300 rpm. That's how they achieve 22 mpg at 60 mph (my Hemi is geared for 1300 rpm at 60, 5600 lbs truck).

Without VVT, especially on a "sports car engine" like the LS series, you should aim for 1500.

Therefore, gear for 1300 rpm @ 50 mph (VVT) or 1500 rpm (no VVT) and you'll be guaranteed to exceed 15 mpg. Probably as high as 17 or so. Then if you have to step it up to 65 mph on the interstate, you'll be at 1690 / 1950 rpm, and still be near 15 mpg, hopefully.

 

[Clutch]

Thats not exactly right, They are bricks facing sideways.:truck:

LOL

 

[mdmead]

Yeah, go rest-mod. I miss my '78. Maybe not my Magnum P.I. shorts, or the girlfriend, but sure do miss the truck.

View attachment 220889

Nice truck you had there Tom!

I've given some thought to restoring an older truck to replace my F-250 Super Duty. I like my truck, but can't see spending the money on a new 3/4 or 1 ton, and would also like to jump to a crewcab.

I'm not sure moving up to a late model fuel injected engine, at least if a person bought a crate engine, is cost effective. I think a simple fuel-injected (TBI) big block makes the most sense for me. My target would be more like 10-12 mpg, but at a much cheaper build cost.

If a person found the right deal on a wrecked truck for parts, maybe going with a late model drivetrain could pay for itself.

I'm not a diesel guy, but I think a case could be made to put a Dodge Cummins drivetrain into an old truck. Prices of older Dodges so equipped are getting pretty cheap.

 

[Clutch]

I'm not sure moving up to a late model fuel injected engine, at least if a person bought a crate engine, is cost effective. I think a simple fuel-injected (TBI) big block makes the most sense for me. My target would be more like 10-12 mpg, but at a much cheaper build cost.
.

That is a good point too...how far do you go chasing mpgs? Might be a fool's errand. While a good ol' 351 EFI will do the trick. Or even a carbed engine. I tend to run from low elevation to high often...kinda why I want EFI. You can put three fuel tanks on those trucks...range wouldn't be an issue.

 

[seanpistol]

Comonnn... do it right and swap in a diesel. Powerstroke or Cummins, but I'd go with the 7.3L and a 6 speed................

 

[jeep-N-montero]

Not a 4-door but still worth a gander http://westslope.craigslist.org/cto/4387036041.html

 

[Clutch]

Not a 4-door but still worth a gander http://westslope.craigslist.org/cto/4387036041.html

Needs to be a crew cab. Several reasons, want to recline the front seats, have a dog, girlfriend can crash out back there during road trips, we recently test drove a DC Tundra...she really liked that back seat.... place to toss my MX gear bags and locked up for when it isn't being used as a camper. Super Cab could work, but it doesn't have 4 doors...I don't want to fight gear in and out of it...have that problem with my extra cab Tacoma now...even with the passenger seat sliding forward the big gear bag is a pain. After using my buddy's crew and having an extra door...it sure is nice.


Can't seem to find a price on this one...too nice for what I want to use it for.

Comonnn... do it right and swap in a diesel. Powerstroke or Cummins, but I'd go with the 7.3L and a 6 speed................

That is always a possibility...they are just so damn loud. I used to operate heavy equipment for a living...I dunno...I am kinda over diesels...but stranger things have happened...it will get the torque and mileage I am seeking....for cheap too. Fits my old man just lug along driving style too. However...Nothing really beats the sound of a V8 gasser.

 

[Clutch]

http://phoenix.craigslist.org/evl/cto/4405664492.html

I love the color combo of this one...would need to find a 4x4 donor chassis...body looks good

That always reminds me of chocolate covered bananas....the house I grew up in had a yellow and brown kitchen....bright yellow sink too that my mom bought.


The '76 my dad had, which became mine. Factory colors (sorry don't know the paint code off hand) was that metallic brown and white two tone, then painted black and white, the black and silver with red pin striping...then finally bright red...by the time I got of hold of it. I drove it for a couple years...blew the engine up, sold it and bought my first Toyota.

His brother also bought one new as well, it was that medium green metallic....I never cared for that color... his brother never took care of it, it didn't last as long as my dad's.

I do think those old trucks look best in Midnight Blue.