small block in a crewcab dually?

[manimal]

Anybody have a 350/383/400 in a crewcab dually 2wd? If so, how does it do pulling the truck around?

[Ziegelsteinfaust]

My friend had 77 with all the bolt-ons, and T700R4. I thought it was just fine for driving. You could feel it was a bit strained with a full load of people, but no big deal. It was you felt the weight faster then you'd ever feel on a 454.

He wanted a CC dually to drive around, and tweaked it for mpg. For what he absolutely had to had he was very happy with it. The big problem was the 350 took a hammering from the heavy truck where the 454 would of lasted longer.

Also my feeling is that a 454 is better suited that with the same bolt-ons, T700R4, and quality of tune. Would likely get effectively the same mpg as a 350, but that presumes you geared each engine for optimal driving rpm.

[spencer_41188]

well it dose verry well i have a 383/nv4500/14bff with a locker 4.10 gears and i can do donuts on dry pavement yes all 4 rear wheels because its a cab and chassis axle

one thing to worry about is the fuel tanks!!! im in the prosses of installing a fuel cell because the factry tanks are so long and the pick up being in the center it tends it starves for fuel when you hit the skinny peddel

[BigBlocksRule]

It'll pull the truck around fine, but don't count on doing much towing.

[manimal]

Thats kinda what I thought. I have a Big Block, I might as well use it. Thanks!

[BigBlocksRule]

If you really want to make it worth doing, add a 4L80E and TBI at the same time. You'll get reliability and better fuel economy. Harnesses are cheap, run it with a factory computer with tune. I've found a few 4L80E cores that came out of trucks that had never towed, changed fluid and filter and dropped 'em in with no issues. If you're going to do that, research the truck it's coming out of, I wouldn't use one as-is if it had been beat on. Expect to pay $250 - $400 for a good one, sell the old TH400 for $200 - $250. New harnesses are $300, just need to figure out the speedo and you're good to go. My current project hauler is an '85, I found a set of '92 gauges with electronic speedo, might be able to do something like that.

Hell, if it's worth doing, it's worth overdoing!

[manimal]

I've got a harness already from a '91 diesel w/4L80e..but no controller. Not sure if I want to go that route or not for the expense. I may just sell the harness and stick a GV on the back.

[BigBlocksRule]

It's waaay cheaper to run a factory harness than with a GV, engine and tranny control in one. Lots of folks would like to have your harness to run a 4L80E by itself...

[rs72z]

5.3 & 4L60E in mine does great. 18 mpg on some short trips. I havent pulled anything with it.

[bilfman]

I just did a 4l80e swap this year. Used a tci controller $600, was a very easy kit to work with, here is a link to the build.

http://67-72chevytrucks.com/vboard/s...d.php?t=537481

As for sbc powered crew, my buddy has a 1988 with a 350tbi and a 4 speed, rolling 4.10 gears. Drive train is full stock, other then a 3" pipe no muffler, truck pulls itself good and is decent pulling a trailer. It isn't an OMG this thing sucks at all, the setup works fairly well.

[andrewmp6]

I depends on how you will use the truck.A daily driver that don't haul much a small block is fine.If your going to haul a lot with it a big block or diesel would be better.

[jitteryguy]

I have a '85 crew cab with a car hauler bed, 350/4 speed. it pull's it self just fine load'd or unload'd.

[D.FENS]

My truck is down with a dead trans (goes fine in reverse but won't do anything in forward gears). Still runs okay but needs a ton of service work.

Been eyeing up a 6.0 swap, like an LQ4, and a 4L80E. Seems like the swaps are cheap enough now that you could do the swap, then sell the stock motor / trans / harness to recoup a lot (or at least some) of the money spent on the swap.

[Desert1957]

Originally Posted by BigBlocksRule

It'll pull the truck around fine, but don't count on doing much towing.

Couldn't be more wrong....

Here is my 350 crate motored small block pulling all this , does just fine.
(SM 465 and 4:10 rear)



Desert

[Keith Seymore]

Originally Posted by Desert1957

Couldn't be more wrong....

Here is my 350 crate motored small block pulling all this , does just fine.
(SM 465 and 4:10 rear)

Fuel economy numbers?

Is that a towing dolly I see between the truck and the trailer?

K

[MalibuSSwagon]

Originally Posted by D.FENS

My truck is down with a dead trans (goes fine in reverse but won't do anything in forward gears). Still runs okay but needs a ton of service work.

Been eyeing up a 6.0 swap, like an LQ4, and a 4L80E. Seems like the swaps are cheap enough now that you could do the swap, then sell the stock motor / trans / harness to recoup a lot (or at least some) of the money spent on the swap.

I would do it. GM uses them in the 3/4 ton and 1-ton trucks, I think a square body crew cab would be even better application of a 6.0L drivetrain due to the weight advantage. It likely would get double the fuel mileage over a 454 as well.

[jimbonice]

As someone who's owned carbed and injected 454's and 460's, V-10 Ford's and Dodges, 5.7 hemi's all in one ton trucks, I'll dispute that fuel injection will get the big gains in economy that people believe. It's incremental at best. A good carbed engine in a 7000 lb truck will do as well as FI and a big motor will do as well as a small motor. 35 years of hauling crap around had proven it for me.
Posted via Mobile Device

[D.FENS]

Originally Posted by MalibuSSwagon

It likely would get double the fuel mileage over a 454 as well.

Not likely, the truck got 8 - 10mpg before the trans started trying to lay down. I would be happy with something around 15 on the highway.

Originally Posted by jimbonice

I'll dispute that girl injection will get the big gains in economy that people believe. It's incremental at best.

First off, does this thread really need that?

Second, LS swaps are fairly often working out to be cheaper than rebuilding a SBC, never mind a 7.4. My truck is already TBi, so the mileage is pretty close to as good as it gets with that combo.

I could spend two stacks doing a bargain basement rebuild on the 454, then another couple on what little aftermarket parts are still available for a 7.4 TBi, then maybe another grand on a 4L80E / Suburban harness to run it. That would probably net me a mileage improvement of maybe 1mpg. Great return for the investment.

Or I could swap it for maybe 3 - 4K, have more HP and torque, and it's mostly factory parts. And have a good running BBC to sell when I'm done.

[jimbonice]

Chill Bill, thats fuel, not girl

[68Timber]

They make good power and rev well, I'd rather have a small block truck or diesel. Nothing wrong with a good big block except the mileage. I'd swap in an LS motor first.

[SSC's76]

with the right gears you would not know the difference between the 2 unless you were to pop the hood. If a 350 is good enough for a suburban its fine for a qcd.

[meatwagon83]

i actually have a lq4/4l80 swap and after talking to a LOT of people with 6 liters in thier duallys i have found that empty they dont get any more than 12-14 mpg, after hearing this several times i concluded that i could rebuild my 454, use the 4l80e and get the same milage while spending less on the swap and get more power out of the 454, sorry this is kinda off topic but these guys keep talking about overdrives and swap so i thought i would throw it out there, btw there isnt anything wrong with a smallie in a dually as long as its geared correctly, although they lack the torque of a big block

[manimal]

thanks for all the replies. I am pretty sure a small block will do the job. I do have a 454 and after some thought, if I am going to get 10-15mpg with either one, I might as well go Big Block. I am however thinking of replacing the TH400 for a SM465 4speed....but not too sure yet.

[86c20]

i have a 10k lbs wrecker and i got it with a new crate 350 ran great but... if you put another truck on the back she would just about move. and got 10 mpg. plus was always reving it it to get her to go. i then tuck that out put the 350 in my 78 monte and love the motor now. i put a 454 in place of the 350 now i dont have to rev it to work the hydro system. i dont have to start of in low gear. and i still get 10mpg with it. i feel that if you have to work a motor hard to get it to do what you want you need a deff one. why beat the hell out of a good small block when you can cruise a big block?? or how ever it works for what you are doing. next for me is change to diesel. more power and mpg and less abouse on the motor to do what i want

[Desert1957]

Originally Posted by Keith Seymore

Fuel economy numbers?

Is that a towing dolly I see between the truck and the trailer?

K

Keith,

Yes it is, very good eye spotting it. Its a "Trailer Toad" keeps all tongue weight off the tow vehicle.Here is a better pic.



Gas mileage is bad, about 8-10, but a square tow rig with a new crate motor is why I personally like it.

Desert