The Boss 72 Chevy 4x4 Cummins Dually

[MrBeast]

Hello everyone, I am new to the group, but I am a long time gear head. I decided to send in some pictures of my current project a 1972 Chevy C-30 Dually.





I bought the truck out of a little town north of Phoenix AZ, I flew out, picked it up, and drove it right straight back. The truck is really solid, and has very little rust being an arizona truck. Allthough from what I can gather about the history of this truck, it probably has over a MILLION miles on it.

The truck has been built a couple of times, a custom duck tail spoiler was grafted into the back of the cab. As well the truck has a custom built towing body on the back of it. But the most interesting thing about it is the truck is that it has the SM465 4 speed, and a 3 speed Over/Direct/Under drive box mounted in behind the factory box under the bed. It is controlled by a remote stick shift setup, it is a interesting setup to say the least.

However Friday as I was out running around town doing some errands, well I stuck my foot in it, and the 454 up and threw too much power to that Over/Under box, and tore the U-joint apart, unknown yet if any internal dammage has happened to the box. On the up side though, I do have a NV4500 just waiting in the wings to go into the truck, as well I have the Advance Adapters Bellhousing, and a Centerforce Dual Friction Clutch.

So over the course of the next week here, I will be getting the tranny installed, building a custom cross member to mount it, and then getting the drive shaft I got with the transmission shortened to hook up to my old H072 rear end.

The rear end will be another future project, it currently has 4.56 gears, and I want to swap them out to 3.90's so as that I can maximise my gas mileage, this is a towing rig after all.

Right now I havent decided if I am going to stick with the custom towing body, or if I am going to sell it in favor of a brand spankin new body built to my specs, we will see on that, but for the time being, I did just install all new LED tail lights in it, and I am going to put new doors on the boxes, with hot rod door latches so as that they will latch nicer and seal better keeping everything inside clean.

As well I will be going with a vintage air unit, and plugging and smoothing most of the holes in the fire wall. Once all of that is done, I am going to tear the truck down, ship the cab and body off to be painted, and I will strip and clean the frame, and box it the whole leingth to make it much stronger, including building new cross members all the way down the frame that will be built much stronger than the stock frame is.

At this point I am going to rebuild the suspention, including either a 4 link or truck arm setup in the rear. The H072 will also get as I mentioned earlier 3.90 gears and an ARB air locker. I am attending college, and later on once I am in the Machinists portion of the class, I am actually going to make a custom set of hubs for my front and rear axles to accept 10 lug wheels, and then the truck will get a set of 19.5" Alcoa dually wheels, wrapped in Michelin Rubber.

On the inside of the cab I am working up somthing special as well, I am doing a custom digital dash, and I will be installing air ride semi style seats.

Other goodies I might have forgot to mention are under the bed I am going to be building custom fuel tanks out of Aluminum that will hold 95+ gallons of fuel. This will give the truck over a 1,000 mile range at 12mpg!

Anyhow, here are a few more pictures, I will keep you all posted on the project.

Oh also on a side note, I am going to be setting up a new shop here pretty soonish as well, so I am going to probably be posting pics on that as well (I am actually with out a place to work right now, it sucks!)

[MrBeast]

Well today was a good day, The old transmissions came out of the truck, and the new transmission made it in for a test fit and measurements.



The first step was removing the 3 speed over/under drive box, and the Exhaust from the truck, along with the drive shafts.



Once that was done, it was time to disconnect the E-brake cable, and remove the remote shifter for the over/under drive.



The next big task was measuring the transmission location so as that I could build the new cross member for the NV4500. As you can see in the picture above I wrapped a 1" ratchet strap around the frame, and used it as a straight edge to get my installed height measurement.



Using a tape measure I measured from the bottom of the strap to the center of the output shaft, it turned out to be aproximately 1"

I then measured the NV4500, and from the center of the output shaft to the bottom of the transmission mount, it is aproximately 4", thus my over all installed height of the mounting surface on the new transmission cross member will need to be 5" from the top of the frame.

I did a bunch of work building a cross member tonight, but I wont have it ready until tomorrow, hopefully I will get some pictures of it then.



In this picture you can now see the Empty transmission tunnel. The next big step was to measure out the installed leingth of the transmissions from the mouting face on the back of the engine. The SM465 is aproximately 24" long to the center of the yoke from the front of the bellhousing, the NV4500 is about 28.5", and the mounting stud is @ 24.5"

Somthing to note here the reason I measure from the top of the frame and not the bottom is that the top of the frame runs straight through this portion of the truck, the bottom side is bowed. There for moving the transmission mount backwards is much easier when you have a common reference line to go off of.

The next thing I had to do was measure back from the mounting face on the back of the engine 24.5" and run my strap around there, then I figured out that I would need a cross member that had a total height of 2 5/8" from the top of the bottom frame flange. This would install the NV4500 with the Output yoke in the same plane vertically in the truck as the SM465 that came out.

Once I had these measurements, I was able to measure out my drive shaft, it turns out that the front shaft will be 26.5" long to the center of the carrier bearing assembly, and the rear shaft will be 52" to the center of the carrier. The reason I measured to the center of the carrier and not to the center of the drive shafts is the front shaft has a slip yoke, and it does not have a constant position, with these measurements the drive shaft shop will be able to find the center of the slip yoke, and cut down the shaft accordingly.

Somthing I was rather suprised with is the carrier bearing out of a 95 Chevy 1 ton X cab Dually Diesel is the exact same with on the mounting holes as a 72! That sure made my life easier.

Hopefully come tomorrow afternoon, I will have the transmission back in the truck, along with the drive shaft, then all that will remain is fixing up a temporary exhaust pipe setup that will make the truck streetable.

Here are a few more pics from today:





In the two pictures above you can see the old 3 speed over/under drive box, and part of its remote shifter assembly. It is a neat setup, I am actually considering rebuilding it with my own personal touches and installing it in another rig down the road.

If I do thought I will be machining a female splined shaft that will connect this box to a 4wd version of the 465, and hard mount the two boxes togeather, then have the provisions for the shifter mounted to it, and the shifter will come up on the passenger side in the location of the 4wd transfercase shifter, as configured by whoever built this truck, the sticks were not well thought out or executed, they would touch in 2nd and 4th gear if you were in high range on the overdrive.



This picture is of the good ole H072 GM rear end, they are hard to come by any more, and even harder to break. This unit is equiped with 4.56 gears, I am going to wind up swapping it out to 3.90's down the line, and adding an ARB air locker.

And for those of you who like 10 lug conversions, I have somthing hiding up my sleeve that is going to make your eyes pop out of the sockets and you shal proclaim "ehy the heck didnt I think of that"

[slammed1]

Nice truck and glad to see more of these older work trucks placed back on the road.

There an extremely long 67-68 cabbed angled flat bed whcih would be great for hauling my Lil bros drag car Impala.

[67_C-30]

Originally Posted by MrBeast

And for those of you who like 10 lug conversions, I have somthing hiding up my sleeve that is going to make your eyes pop out of the sockets and you shal proclaim "ehy the heck didnt I think of that"

I have a set of 19.5's with simulators that have I have been toying around with putting on my '67 C-30. I would like to find a NV4500 for mine as well.

[MrBeast]

Originally Posted by slammed1

Nice truck and glad to see more of these older work trucks placed back on the road.

There an extremely long 67-68 cabbed angled flat bed whcih would be great for hauling my Lil bros drag car Impala.

The reason I bought this truck is so I can pull trailers because right now I have no way to move in-opp vehicles around, I still have a 93 Z28, a 79 TA WS6 6.6, and a 71 442 up in Montana that I need to go get so I can work on them. Once I get things setup to where I can work on it, I will be building a 36' deck goose neck that will be able to haul 2 cars, and it will have a winch so I can pull non runners on. I spent a lot of time doing the math and I have the dove tail designed so as that I can pull on a car with a 108" whel base and 4" of ground clearence with out scraping!

And actually the guy who posted below you has the exact truck of which you speak.

[MrBeast]

Originally Posted by 67_C-30

I have a set of 19.5's with simulators that have I have been toying around with putting on my '67 C-30. I would like to find a NV4500 for mine as well.

I actually scored when I got mine, I picked up the NV4500, Hydraulic cluth peddal and assembly/lines, drive shaft, and the 14 bolt out of the same truck a guy was parting out all for a grand. If you keep your eyes out there are more and more of them showing up out there all the time.

I need to do some heavy resarch though because from what I understand the NV4500 is limited to about 500 hp and 450 ft/lbs, that being the case my current 454 will be capable of shredding this transmission.

I have been watching your thread as well, I am going to be really interested to see how that 6.5 works out in your truck, Eventually in the Boss Hoss I want to stuff a Duramax in it, but that is going to be a little ways down the road, unless that is I get my hands on a Cummins 12 valve.

Does your truck have the H072 rear end?

[see ten]

That's a nice truck and it sounds like you have some big plans for it as well! I'll be looking forward to seeing how it comes out. Is that your blazer in the background as well?

[Spray-Bomb]

Pretty darn cool if you ask me

Shoot you got more accessories than my ol GMC (accept for the Kilroys that go on the bug shield)

[MrBeast]

Originally Posted by see ten

That's a nice truck and it sounds like you have some big plans for it as well! I'll be looking forward to seeing how it comes out. Is that your blazer in the background as well?

Yeah, that is my 72 K5, with a 454 heart transplant!

[MrBeast]

Originally Posted by Spray-Bomb

Pretty darn cool if you ask me

Shoot you got more accessories than my ol GMC (accept for the Kilroys that go on the bug shield)

I am surpised to see the spoiler on your truck and the visor, they apear to be the same ones as on mine. Allthough the spoiler on mine is moulded into the cab.

[67_C-30]

Originally Posted by MrBeast

I actually scored when I got mine, I picked up the NV4500, Hydraulic cluth peddal and assembly/lines, drive shaft, and the 14 bolt out of the same truck a guy was parting out all for a grand. If you keep your eyes out there are more and more of them showing up out there all the time.

I need to do some heavy resarch though because from what I understand the NV4500 is limited to about 500 hp and 450 ft/lbs, that being the case my current 454 will be capable of shredding this transmission.

I have been watching your thread as well, I am going to be really interested to see how that 6.5 works out in your truck, Eventually in the Boss Hoss I want to stuff a Duramax in it, but that is going to be a little ways down the road, unless that is I get my hands on a Cummins 12 valve.

Does your truck have the H072 rear end?

My '67 C-30 has a 14 bolt out a '97C3500, and my '69 C-30 ramp truck and '69 GMC 3500 dump truck has Dana 70's. I put the Dana 70 in the ramp truck, but the Dana 70 was already in the dump truck. I have the original HO72 that came out of my '67 C-30. It was too short to do wheel flares, so I put the wider 14 bolt in there.

[67_C-30]

BTW, where are going to get 3.90's for the HO72? The highest set I've found is a 4.10. Are there any higher than the 3.90 available?

[LUV2XCLR8]

Nice rig

[MrBeast]

Originally Posted by 67_C-30

BTW, where are going to get 3.90's for the HO72? The highest set I've found is a 4.10. Are there any higher than the 3.90 available?

Randys ring and pinion got em! But all they offer is a 3.90. Which leads me to my next post....

[MrBeast]

Today was kind of a sucky day, the drive shaft shop didnt finish my shaft, and UPS Next day air Failed to be next day with my throw out bearing. So absolutely nothing what so ever got done today.

So not being one to disapoint, I will put this up there for anyone who is wondering weather or not it is worth making the NV4500 swap.

As my truck is configured it has currently 4.56 gears, and stock it had a SM465 4 speed. Now we are going to Ignore the Overdrive that came in the truck seeing as how it has currently been unidentifyable, and thus is unservicable.

Currently with the dually I am running 235/85R16's that stand 31.5" tall, There for it makes 636.54 revolutions per mile. To travel at 70 MPH the truck will have to turn 3,386 RPM with the 4.56 gears and the 1:1 final drive ratio of the SM465.

So naturally at that engine speed the engine will suck fuel like none other, and be short lived.

Now the NV4500, with 4.56 gears, and the .73:1 overdrive. The engine will have to turn 2472 Rpm to make 70 MPH. That is 914 RPM less than with the SM465.

The next thing to consider is my rear end swap. I am installing a set of 3.90 gears. This will let the engine roll back and run at 2,114 RPM, 358 RPM less than with the 4.56'es and a whole whopping 1,272 RPM less than with the SM465!

There for with with the two swapps I am doing, you can really see how this will allow the truck to get much better milage, but boy howdy I am not done yet.

As a former profession I used to be an over the road truck driver, I had my own truck and trailer, and one thing I really did pick up on is a series of tires produced by Michelin called the XDN-2. Now why is this relavant to chevy trucks you might ask?

Well here is why, I am building my truck to drive, I am going to work the holy dog snot out of this truck, It is going to see use every day of the week most of the time, and thus it is time for a small history lesson.

The Michelin XDN-2 was developed for the Ice Road Truckers that run in North Eastern Canada, (yes the same guys as the tv show) they have a special interlocking sipe pattern that allows the tires to have extremly superior traction in snow, ice and wet conditions.

So you ask, what does a guy in South Texas need with a good ICE and snow tire you ask? Well as a total fluke when Michelin made this tire, the siping actually makes the tire extremly efficiant at HEAT DISAPATION it was a totally unintened outcome, but it has worked out great. Because of this phenomenon there are class 8 big trucks that have run these tires over 300,000 miles!

Now the bad news, Michelin doesnt make the XDN-2 in anything smaller than a 22.5" wheel. The good news is, there is the XDS2, it comes in a 225/70R19.5!

The XDS2 stands 32.4" tall, it will turn 625 revolutions per mile, that is 11.54 revolutions per mile less than the tires I am currently running, Why is this such a big deal you ask? well because it will knock the Engine RPM's at 70 MPH down to 2069 RPM! That is 1,317 RPM's less than with the current tires, SM465 and the 4.56 gears!

Is it all worth it, I certanly think so!

[MrBeast]

Originally Posted by 67_C-30

My '67 C-30 has a 14 bolt out a '97C3500, and my '69 C-30 ramp truck and '69 GMC 3500 dump truck has Dana 70's. I put the Dana 70 in the ramp truck, but the Dana 70 was already in the dump truck. I have the original HO72 that came out of my '67 C-30. It was too short to do wheel flares, so I put the wider 14 bolt in there.

I have a 14 bolt out of a 95 dually as well, I also have been seeing a girl who's grandpa has a 72 GMC C/20 with a 396, I have seriously been thinking about doing the dually swap on it. I also can get the whole front suspention out of that 95 still, so that might be an option if I do so.

[67_C-30]

My plan, at least for the time being, is to drop down to 3.42's in the 14 bolt. That will put me at around 2700 at 75 mph. With the low first gear of NP-435-GA, I will have no trouble getting it moving with a load. I had this same set-up in an '83 C-30 with a SM465 and 3.42's with a N/A 6.2 and it worked out great. That truck averaged around 20 mpg. If I had an extra $2000 laying around, I'd leave the 4.10's and put a Gear Vendors OD behind the NP-435.

[MrBeast]

Originally Posted by 67_C-30

My plan, at least for the time being, is to drop down to 3.42's in the 14 bolt. That will put me at around 2700 at 75 mph. With the low first gear of NP-435-GA, I will have no trouble getting it moving with a load. I had this same set-up in an '83 C-30 with a SM465 and 3.42's with a N/A 6.2 and it worked out great. That truck averaged around 20 mpg. If I had an extra $2000 laying around, I'd leave the 4.10's and put a Gear Vendors OD behind the NP-435.

I hear you there, I did a ton of research before arriving at my current setup, I am going to be working with the 454 for a while, so I needed to get the R's down to get any kind of Milage, Eventually a Cummins or a Duramax will get stuffed in the truck, and with the way I am setting it up it will keep either engine in its happy RPM range at cruise.

I have been looking around, I want to find a 4x4 GMC Sierra Grande that I can put the 454 out of this truck in. They are kind of hard fo find at a decent price any more though. I will probably wind up having to clone one. But I have a lot of work to do before that point.

[MrBeast]

Enervation has set in.

So today I busted my butt at work and knocked out all of the calls I had to do and got through my day so I could go get crackin on my truck.

As soon as I walked into the shop, I got my first piece of bad news, Summit Racing sent me the wrong throwout bearing, it was only a day late, and the wrong damn part. Even after I had called them twice to ensure it was the right bearing. So much for being through.

So as it were, the throwout bearing that came from my SM465 was still in really good shape so I opted to use it instead of goofing around any more. So we got everything Assembeled, stuffed the tranny up in the hole, and it stoped 1/2 an inch short of the engine, and would go no further. So after an hours worth of pushing shoving and playing with it, Back out the tranny came, only to discover that the needle style pilot bearing supplied by Advance Adapters was the wrong one for my NV4500!

So I figured ok, pull the new one out and stuffed a plane jane brass pilot bushing back in the crank, stuff the tranny in and I would be in buisness. Not hardly, I stuck the slide hammer in, gave it one whack and little pieces of needle bearing when flying, I spent the next 3 hours with a hammer, chissel, and a die grinder removing little pieces of pilot bearing from the back of my crank, I did it all with out maring the crank shaft.

So finally, the transmission went back up in the tunnel, slid into place and bolted in. Luckily the hole I had cut for the shifter was in the perfect location.

At this point I started to feel a lot better, I was starting to get excited, but my excitement would be short lived, When I stuffed the drive shaft in the hole, The front shaft turned out to be the correct leingth of 26.5" center of the front U-joint to the center of the Carrier bearing, but the back shaft was suposed to have a mean leingth of 52.5" from the center of the carrier bearing to the center of the rear U-joint. (Mean meaning in the middle of the slip joints travel)

So back to the shop it went, and my truck is still waiting.

More updates tomorrow.

[MrBeast]

Originally Posted by 67_C-30

BTW, where are going to get 3.90's for the HO72? The highest set I've found is a 4.10. Are there any higher than the 3.90 available?

I checked with randys ring and pinion this morning, they arent carrying them right now, however yukon gear has them listed on thier site.

[72BlckButy]

Great looking truck!

[MrBeast]

Originally Posted by 72BlckButy

Great looking truck!

Thank you!

[MrBeast]

Well today was a good day, I got my drive shaft, and it was right this time, the shop did right by me and didnt charge me to fix it.

I started out the day by installing the new cross member I built, I constructed it out of 1/4x2x4" hot rolled box tubing, and 1/4x4" flat bar. It is extra stout, actually twice what it needs to be, but that is the way I like it!





Once I had it in and mounted I was able to breathe a big sigh of releif, I think it came out pretty good, allthough I will have some finishing to do on the cross member, but that can wait until the truck comes apart for paint.



Seeing it at this point made me so happy, I was totally stoked to have the transmission finally mounted up right.

then I got the drive shaft installed, and it went in like a charm the first time, once I had the stick installed, and everything buttoned up, as well as the E-brake Adjusted, I was back in buisness!

The only thing I have to do to get the truck street legal again is install new exhaust, I had to cut the old pipes out so as that I could install the transmission cross member.

Oh, and here is a little preview of another project im workin on on this truck...



Catch yall next time!

[MrBeast]

Well today was a good day, I worked my ass off tonight and got the exhaust cut up and rewelded togeather and stuffed back under the truck, I wound up having to pound the H pipe semi flat to get it to clear the NV4500, Then I had to drill out the header flange holes a bit bigger to get them to mount up, but all in all I was able to drive it about 16 miles home tonight, and the truck ran like a dream. It pulls really hard through the gears, and accelerates like a beast when you stuff your foot in it, and at 70 MPH it is just hummin along nice and easy.

I am really starting to love this truck.

This weekend I have to install 2 more exhaust mounts, then once that is done, all that will remain is getting the licence plate light done, and I am set to get it registered and back on the road. Of course I need to find the perfect 1972 Plates first!

Hopefully this weekend I will be able to get a lot more pictures posted. Oh and the bad news is that the rear main seal is leaking, but that isnt going to keep me from getting it on the road, it will just mean watching the oil level for a while.

[Yukon Jack]

What a great project - sure makes for good reading. You go after a project with great enthusiasm!