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1975 Chevy Dually Rework

cage2592

cage2592

Administrator
I say Rework because this was my daily Driver for 13yrs. Its been sitting for the past 5yrs in our shop and we are getting it fixed up again to daily drive.

So this is my 1975 Chevrolet 454, Dually (DRW) C30 Camper Special (10,000 lb). It was purchased to replace our 1984 GMC K3500 Diesel, Single Rear Wheel (SRW). The 84 was wrecked and totaled. Once totaled, we stripped the Dana 60 front axle, spring hanger brackets, TH400 and NP205 Transfer case out.

A month later (18yrs ago) this Dually was bought. It currently has 398,000 original miles on the 454. Only changed both head and intake gaskets about 10yrs ago. You may notice from the pictures that the front wheels are not the convex dished dually wheels normally found. After we bought this dually, we took out the entire stock 2wd system and swapped in the front drivetrain from the 84 GMC mentioned above. To make this work, we bought an aftermarket bolt-in crossmember from Offroad Design. Other than that, the frames are pretty much identical.

How it sits below is a 6" front suspension lift, rear 1.5 ton leaf spring pack and shackle kit for a 6" lift. 35/12.5x16 BFG AT on AR Baja wheels. Both rear sides have a billet 2.5" spacer between the tires for a 1" sidewall to sidewall clearance.

Full Suspension kit from Offroad Design. Springs were done by a custom spring shop.

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So then my wife decided that since we use the big International 4900 to pull trailers and not this truck anymore, why not make it a Single Rear Wheel. (She always hated buying tires for this truck). I was originally against it as this has a Dana 70HD rear and I didn't want anything smaller. So I pulled off all the tires and started measuring the front axle width and the rear. I then remembered that the 1984 Dana 60 front axle was wider than the original dually 2wd front end. The difference now in the front and rear was only a few inches. So we pulled the dually fender off one side and mounted up the old 16x8's with 4.5" back spacing on the front and rear for another look down the side to see what it looked like with the rear sticking out further than the front. We were in luck. The rear was out only 2.5" more.

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So I get on Summit and order up the fronts of 16x8 and 4" backspacing and rears of 16x8 and 5" backspacing. The kicker is we had to order the fronts and rears as a different manufacturer because the same Manuf. didn't have the BS we needed. I searched all over the internet and couldn't find any info on the wheel perimeter hole size or spacing so I was hoping they looked identical. They turned out great and you cant tell unless you know what to look for. Got them in and the new Dick Cepeks. We ended up with the rears out only 1" more than the fronts. Oh, and the truck got a wash.

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I like it the way it is, but your truck. '75 crew dually is very hard to find (I know I tried to find one many years ago).
 
When we pulled the original 4spd trans out of it when we did the 4wd swap, we had to cut out the tunnel and fab a new one with a Lokar automatic stick to go next to the 4wd shifter. Interior is good for now but will be updated this summer.

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77cruiser said:
Send that BB to Mark & have him do some tow magic.
Click to expand...
Plan this winter is to install a Gear Vendors unit behind the NP205 transfer case. It will be a lot easier than a car as we have tons of room and there is an 'intermediate shaft' that just needs to be shortened and balanced. no issues with weird angles. That will go quick.

Yes Sir. This is the BB I always mention that I want to go to Mark Jones. I haven't decide whether to pull this one and send it, or just have him use one of his. PRO would be that I can continue to drive this one while waiting for his. CON on sending this one, I may be waiting a long time pending his backup or scheduling and not driving. I guess it would really depend on the cost difference, then his schedule.

After that will be the AC.
 
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Some might be asking what will happen with that huge open area where the dually fenders went. As you can see, I started on some bodywork. The plan was to order new longbed side panels, cut these out and weld them in. I was holding off as each side is $750 with shipping so $1500 for both. Then the pain of cutting, welding, straightening.

I'm glad I held off because a gentleman about 2hrs away was selling an entire STRAIGHT longbed for $150 !!! We drove the International over last week to pick it up. Pictures of that when its dailight out and we unload it.

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So I have the newer Fleetside straight bed that I bought in the shop. My issue is I cant decide on a route to go. Ill post up pictures of it but it has minor surface rust and will be cleaned up as I media blast it.

My problem is the Fuel fill inlets.
As you see in the pictures above it has the original style 73-78 round fill with external cap and there is on on each side for the dual tanks.
The new bed is from a 79-87 and only has the fill on one side and is the square door for a single tank. As Per below
1646397217762.png

So the routes to go:
1. Cut the rounds out of both sides on my original bed and weld them into positions on the new bed. Most work but will look original.
2. Leave the original square in the passenger side of the new bed. Find a driver side square for the new bed and weld it in. Medium work but look original and for a 79-87 truck
3. Leave the original square in the passenger side of the new bed only AND, tie both the tanks together with a equalizing hose (like on a dual tank semi). Less work. Allows fill on one side for both tanks.

Thoughts and or other options?
 
I had the exact same issue when I replaced the bed on my '80 Chevrolet 4x4.

What I did was probably the easiest to do, but others might not like it. I rerouted the fill on the passenger side to inside the wheel well (front of the wheel well) so it was easy to fill and was kind of hidden, but I didn't have to disturb the bed panel at all.
 
My '73 has 2 tanks and the pass side tank was exactly as Kevin states, the filler just crawled up the inside of the wheel house, no door.
 
What it looked like yesterday with the new tires and wheels. The rear wheels have a deeper BS to compensate for the dually rear still installed.
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Yes. Its a Dana 70 with a locker in the rear and I don't want to take it out. The rear spring pack came out of a Military CUCV / M1008 which are 1 1/4 ton springs. When a local spring shop rebuilt them, they took out the old one inch overload spring and replaced it with a 1 1/2 spring. It still rides pretty decent but I want it to drive like a truck.

Right now with the way it sits, the rears stick out 1" further than the fronts. Noticeable to me but no one else has said anything.
 
Looks just fine to me..... as long as you don't squat the rear.

My '80 1 ton was up that high too.... didn't have any nerf bars or steps and always had to help Lisa get in.
 
So an update to the truck.

I've been driving it a few days a week to work. about 60mi round trip to work. 95% of that is on I-10.
It has a TH400, NP205 Transfer case, 4.10 gears and 35" tires. I don't like to max it out on the HWY but my RPMs are about 3000 @ 72mph.

Last night I received the below:
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Sitting in the truck so I can get my new driveshaft measurements. The output shaft yoke ended up with only 1/2 exposed and NOT like the 2.5" shown in the picture. Dropping off the old shafts today. Plan is to have it running this weekend.

This should put me 2300RPM @ 72MPH or a happier to run 2400RPM @ 75MPH.
 
We are also still prepping for the new straight bed to go on. As you may remember, the new bed is off an 84 with one gas fill door on the passenger side.

I decided to run one of these on the bottom of each saddle tank.
Capture.JPG

They are already on and working well. Now I fill up on the passenger side and the two tanks are connected with a 5/8 hose through these. As I fill up the Passenger side, the driver's side fills as well. there are ball valves under each tank to isolated them if needed.

We also installed the new 750cfm Mechanical Edelbrock Carb. Its ok. I prefer AED carbs but didn't want to spend the money yet on the mostly stock 454.

Also installed the new ROBBMC Fuel pump and regulator.
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