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Dewey72 01-26-2014 07:36 PM

72 Cummins swap
2 Attachment(s)
Trying to figure out what to do for a fuel tank. I would like to swap out the front seat to newer one and move the seat rearward. I'm going to run 4" exhaust over the rear axle so a near mount tank is kind off difficult without making a custom tank. Plus I think I will run nerf bars but not sure if the saddle tanks will clear. What have other guys done? Looking for advice.[ATTACH]Attachment 1206231

Attachment 1206235[/ATTACH]

gerfunken 01-27-2014 02:59 PM

Re: 72 Cummins swap
So, I actually went with a 31-gal fuel tank from a square body suburban. It fits cleanly between the rails. I had to remove the back two cross members, turning one around to provide the front mounting bracket. As far as exhaust goes, it looked like I had more of an issue from the rear brake line bracket than from the exhaust. I've got a little bit of room, but not an extreme amount, and will be looking at the exhaust routing next.

The mounting of the tank is one the last couple of pages, but I can always take more pictures if you need.

Dieselwrencher 01-27-2014 03:38 PM

Re: 72 Cummins swap
I have some pictures in my build thread when I stuck a 40 gal burb tank from a square body in my Longhorn. I had to move all the same things Scott did as well. I ended up ditching that when I went to air ride though. Now I have to build a tank for it. :lol: By the way, nice swap you have going.

BigRed76 01-27-2014 03:45 PM

Re: 72 Cummins swap
Is your truck 4x4? If it is and is lifted at all then I'd think you could run a rear mount tank and still have room for 4" exhaust. I installed a 25 gal. square body burb tank in my '71, and after moving those rear crossmembers it fits like a glove...but I had absolutely no room for exhaust back there since mine's 2wd and lowered 5.5" in the rear.

I picked the 25 gal. tank because it only hangs down a few inches below the frame rails, whereas the 31 gal. & 40 gal. tanks hang lower.

Dewey72 01-27-2014 04:50 PM

Re: 72 Cummins swap
Forgot to give ya the specs. 72 short wide 93 12 valve, nv4500, 205, 60 front and 70 rear 4" lift . Not sure if the rear tank will clear the 4" being a SW box. I'll post more, newer pics later. Everyone likes pictures.

gerfunken 01-27-2014 10:17 PM

Re: 72 Cummins swap
From my thread...

I've done some cursory measurements, and also checked online. There are three sized tanks that the Suburbans came with:
25 Gallon: 28-3/4" x 28-18" x 10-3/4"
31 Gallon: 28-3/4" x 28-18" x 12-3/4"
40 Gallon: 35" x 28-3/4" x 13-1/8"
(Sizes verified on LMC Truck, O'Reilly & Napa Auto websites)

I decided to go with the square-body suburban 31 gallon gas tank. That required a little bit of fabrication on the back end of the truck.

To start, the rear cross-sill (the one with the light plug) came out, and was rotated 180-degrees, and became the front brace for the fuel tank.

This effort was followed for quite some time with lots of measurements. I needed to have the fuel neck clear the frame, but at the same time not be so tall as it would bump into the bottom of the bed. Likewise, I needed to play with it front-to-back as so to sit between the bed rails. Once that was done, I finished the calculations and made the brackets.

Then it was a matter of getting it into its final resting place.
***Note: The rear brake line is a temporary solution, and will be getting adjusted either today or next weekend. I'll re-work the bracket and provide more substantive support across the frame before joining to the soft-line on the axle.

BigRed76 01-27-2014 10:37 PM

Re: 72 Cummins swap
In that case I'm not sure that any of those tanks would fit in a short bed. Might be more logical to run a 67-72 suburban tank.

Dewey72 01-31-2014 11:47 AM

Re: 72 Cummins swap
3 Attachment(s)
Got my IC pipes done but not sold on the color. Might powder coat later. Anyway I think they turned out OK.
Attachment 1208616
Attachment 1208617
Attachment 1208618

ryanroo 01-31-2014 08:58 PM

Re: 72 Cummins swap
Pipes look pretty darn clean to me.

Dieselwrencher 01-31-2014 09:57 PM

Re: 72 Cummins swap
Looks really nice!

Vintage Windmills 02-01-2014 04:39 PM

Re: 72 Cummins swap

Dewey72 04-10-2014 04:05 PM

Re: 72 Cummins swap
3 Attachment(s)
Got my cab back from the blaster the other day.
Attachment 1240229
Attachment 1240230
That blasting sure finds the rust. I knew I needed floor board and rockers but found some rust under the windshield. Looks like I need to find a donor cab to cut part of the windshield frame out and weld into mine. In less somebody has a better idea.
Attachment 1240231

Dieselwrencher 04-10-2014 08:59 PM

Re: 72 Cummins swap
Yeah, sand blasting will sure find any soft spots in the metal. If you look in the 67-72 parts section on here, you might find a cab someone is cutting for patches and you might be able to get one that way.

Dewey72 04-11-2014 04:19 PM

Re: 72 Cummins swap
3 Attachment(s)
Took so more pictures with the cab off.
Attachment 1240629
Attachment 1240630
I cut the top two rows out of my IC to make it fit.
Attachment 1240628

ahsom79vette 04-23-2014 01:41 PM

Re: 72 Cummins swap
Nice job! Any idea on what you'll end up having invested in just the Cummins swap?


Dewey72 04-24-2014 03:47 PM

Re: 72 Cummins swap
Not sure on the investment. I am keeping all receipts from everything but scared to add it all up. Maybe some day.

Dieselwrencher 04-25-2014 07:52 PM

Re: 72 Cummins swap
Don't add it up until you can drive it. Just speaking from experience. It might make ya cry. :lol:

superduty_59 05-01-2014 07:45 PM

Re: 72 Cummins swap
Great project! Keep up the good work!

rgreathouse 08-05-2014 04:58 PM

Re: 72 Cummins swap
Keep it up, looks great! With your transfer case linkage did you have to cut the floor at all? Or did it stay inside the opening? I have an nv4500 and 29
Spline np205 and with the advanced adapters bracket it sticks the tcase shifter pretty far away from the transmission shifter

Dewey72 08-05-2014 06:22 PM

Re: 72 Cummins swap
2 Attachment(s)
Both shifters came out different. Just a weld and cut job for the new openings.
Attachment 1286122

Attachment 1286123

shopteacher 08-30-2014 10:01 PM

Re: 72 Cummins swap
great project and I'm Subscribed to this one! could you show a couple of pictures of you engine mounts please!

What color are you going with?:metal::metal:

Dewey72 09-02-2014 10:41 AM

Re: 72 Cummins swap
I used a engine mount from autoworld. I'll see if I can get some pic's for ya. I think I'll keep the color the same. The truck was my Dad's bought new in 72.

Nitis 09-02-2014 01:32 PM

Re: 72 Cummins swap
Back to your original post. I don't blame you for removing the tank from the cab but you won't gain any more room to move the seat back. All the seats always hit the cab above the tank before they hit the tank. Unless you want a seat that sits at a 90 degree upright there's nothing to gain

Dewey72 09-02-2014 04:17 PM

Re: 72 Cummins swap
Not sure if I'm going to use the factory tank or not for sure yet. But was thinking more of room for some speaker boxes. Try to hear over the diesel noise. Speaking of that is anyone running a flowmaster diesel muffer and what does it sound like. Got a 4 inch on mine and sounds cool but not sure under load what it sounds like.

Nitis 09-02-2014 05:48 PM

Re: 72 Cummins swap
Ok just didn't want you getting your hopes up! But yes that space is definitely useable for something.

Also you said your using a cummins from a 93?

From my limited time in the diesel world but aside from the looks of a 4" I don't think you will gain anything performance wise from it. I thought that only mastered once you get up over 500-600 horse power or something. Just a thought maybe you can split it or something?

Again I'm no diesel mechanic just throwing it out there

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