Need everyones help here

[bigblock79]

ok i bought a 79 crew cab dually 4x4. it is 400 sbc 400 turbo im the 3rd owner. its gear 410 so gas milage sucks all i want is a 4x4 crew that will get the gas milg of a 308 gear 1/2 ton 4x4 would get. i do not want a dually so can i convert it to 3/4 ton reg wheels and still keep the same rear ends or what would ya do ill get pic torm. thanks

[spaseghost]

why not just put in 3.08s? ive got 2.73s in my bb, and i would never change them unless i pulled the th400 and put in an overdrive.

[Driveway Dreams]

I wondered the same thing...why not just change your gearing? Are you 100% against the dually? If so, reasons? Sorry, I just think if you have the dually, keep the dually. But that's because I want a crew DRW truck for a family cruiser.

[D13]

Can't get gears for the rear of 1 ton OR 3/4 in anything lower than 3.43's. In theory there are some 3.23's aftermarket but no one seems to have done this.
Remember, 3.43's with 235-R80-16's is about the same as 235-R78-15's.
And since it's a 4x4 a Gear Vendors wil be an issue (side note - why pay $3000 + for a O/D that saves you $600 a year?).

Things to do, in order.

1. Swap in 3/4 ton axles with 3.43's, easy to find complete axles. Find a mud bogger who wants the heavy axle and the 4.11. Or do the R&P in the front and swap the rear. At the same time go single wheel in the back, sell the dually fenders to finance the swap (less tires = less resistance = better mileage).
2. Install the tallest tires you can comfortable fit. 80 series commercial truck tires are great. Don't forget to adjust the speedo.

now, the stuff you can do that will never pay you back (you'll spend more than the gas savings).
1. Get rid of the 400 and put in a 350. 400's suck gas by comparison to a nice 350 with a torque cam. And you're not going to drag race it right? Just remember there's a lot of 1 tons out there with 292's in em...
2. Swap out the TH400 for a 4L80E with a stand-alone contoller.
3. Skip above and swap a complete 6.0/4L80e out of 2001 or newer.
3. Drive slow.

[nekkidhillbilly]

6.2 diesel swap

[Damien]

What do you get for mileage now? Most 1/2 ton 4x4s I've driven get 8 to 10 MPG with 350s.

[bigblock79]

i got the truck taged today. it got good power. if u just drive like a 80 year old on back roads its not that bad on gas. 4 wheel drive works good i took it to the cow pasture. went down the back side of the farm. went thru a swapin bottom just put it in low range loc and gave it some gas and it plow its way thru throwing 20 foot roster tail. i thank ill covert the front and put a single wheel rear in it. what the best way to convert the front to reg 3/4 ton front wheels

[Jonboy]

It seems to me that 1 ton dually 4x4 and fuel mileage are mutually exclusive. I think you can have one or the other.

[bigblock79]

i was looking for a crew cab to bulid me a short crew cab . but i found this beast

[spankbomb]

Just find someone who has the SRW hubs for the front Dana 60 who wants to convert to DRW hubs.

Recommend finding your local rockcrawling website or go to pirate4x4.com.

Later,
Jon D.

[ghettoluxury]

srw hubs the cheapest you will find and they already have rotors and studs http://cgi.ebay.com/ebaymotors/2-Dan...Q5fAccessories
Not sure if your rear is dana 70 or 14bolt.if it is a 14 bolt a set of hubs from a srw will interchange just make sure to get the brakes also or go with a rear disc conversion.
3.43's were common in the d60, d70, and 14 bolt these will save you on gas and still alow you to keep the beefy axles. If you do decide to go 3/4 ton front or even 1/2 ton front, selling the dana 60 should pay for what you need it is worth about 400-600.

[Dooley]

Originally Posted by ghettoluxury

srw hubs the cheapest you will find and they already have rotors and studs http://cgi.ebay.com/ebaymotors/2-Dan...Q5fAccessories
Not sure if your rear is dana 70 or 14bolt.if it is a 14 bolt a set of hubs from a srw will enter change just make sure to get the brakes also or go with a rear disc conversion.
3.43's were common in the d60, d70, and 14 bolt these will save you on gas and still alow you to keep the beefy axles. If you do decide to go 3/4 ton front or even 1/2 ton front, selling the dana 60 should pay for what you need it is worth about 400-600.

Remember, your rear ratio will be limited to what is available for the front Dana 60F.
I've bought a half dozen new and a few used 30 series 4x4's,(GM introduced the K30 in 1977 model year) over the years. My trucks have had 3.73, 4.10, and 4.56's. I have never seen a Dana 60F with a gear lower than 3.73, or a a GM K/V series dually with a Dana 70 lower than 3.73, not likely 3.43's were ever common or available for square body 1 ton 4x4 trucks. I have seen a 3.54 listed in books for a Dana 60F/70 rear but, never known anyone to have one of those in a 30 series 4x4 either. Certainly not common.

If your truck was a chassis cab and came equipped with a 14 bolt rear, there will be many more gear sets available but, won't find them for the Dana 60F.

[68 TT]

Do you really need the 1-ton or even a 3/4-ton truck in the end?

What if you just picked up a 1/2-ton 4x4 short bed truck and used it for parts. It would get you the short bed you want and the single wheel differentials all ready geared alike. I see them pretty often for $1000.

You could put all the DRW parts onto the 1/2-ton chassis and turn it into a flat bed or just sell all the spare parts.

The gear change alone could cost you nearly as much as the parts truck.

[bigblock79]

it came as dually my goal was to find a crew cab that i could bulid me a short 4x4 crew but found this thing. i got a 78 short bed and 1/2 ton axels i bought to do this with. would a surban frame be better

[pig rig]

well being the owner of a few big block and small block crew cab dually Im fairly confident in say'n crew cabs don't get good gas milage
(1) your truck was built in early part of the fuel crises and the big three still belived if you can aford to buy this big of a truck you can aford to pay for the gas
(2)how much power will it take to push a 6000lbs + truck down the road? and don't you think it will take above average gas to make that power

I hear guys ask the same question all the time and my standred answer is toyota makes a hell of a 4x4 crew cab
hate to be a smart ass but if a crew cab dually is getting 12mpg congrats to you.
I have one that I drive every day that gets about 14mpg but I've got in the neighbor hood of 15g's into the drivetrain along with lots of hours of trial and era to get it there so wheres the pay off

[68 TT]

The total weight of the rig and the massive amount of rotating mass of the DRW setup is going to make it tough to get anything that resembles good gas mileage but if you can lighten up the whole thing with the 1/2-ton chassis and SRW axles plus an overdrive transmission you have a fighting chance.

Don't forget the rear disc conversion is worth about a 70 pound reduction in rotating mass which will have a nice impact upon gas mileage and power to the ground.

[bigblock79]

so what would ya do just change out the rear to a single and leave the front alone or change it out all togther to 1/2 ton how about a burb frame

[BLE 'BURBAN]

If it were up to me, I'd just bolt in a gearvendors overdrive unit for the mileage and still keep the 4:10's for towing power.
With a G.V. overdrive unit installed and activated you'll have the gear ratio of 3:20's
Here's a link to their website gearvendors overdrive unit

[Dooley]

Originally Posted by bigblock79

it came as dually my goal was to find a crew cab that i could bulid me a short 4x4 crew but found this thing. i got a 78 short bed and 1/2 ton axels i bought to do this with. would a surban frame be better

I was asking if it was a chassis cab model, not a dually, because GM sold 2 and 4 door trucks without pickup boxes. The dually chassis cabs did not have the same rear axle as the dually pickups. The chassis cab axle is narrower even if it was a dually.

[bigblock79]

the man told me it came with a dually bed orig. in the pic above what does the D big dooley means. my truck got a 10000 gvw it says camper spiceal

[bigblock79]

pic

[bigblock79]

to me a dually is a truck with a reg bed with rear fiberglass fenders a chassie and cab to me is just a ton truck

[ghettoluxury]

Since your truck has a Dana 70 it is a dually not a cab chassis.

[bigblock79]

what can i do to make it a single wheel 8 lug 3/4 ton wheels

[GMC91]

Not trying to take from the thread or anything, but I have to ask. What is the usuall gas milage of a 86 3/4 LWB 4x4? It has a 305 with a TH400 and 3.5? rear end. I plan on a 2 in lift with some 30's under it. Just wandering if it will get mayby 10-13MPG