1991 Cummins Suburban

Cody1771

Explorer
Hey there! looks like a cool project! soooo few suggestions on my part. check out 4btswaps.com. its a website dedicated to cummins swaps in chevys and the guys on there are very helpfull. 2nd i would suggest going with a 12 bolt front end. i was going to put a 6BT in my half ton and was told that the 10bolt front axle would not hold up to the weight (1100lbs) of the 6bt. and the 1/2 tonn frame wouldnt hold up to the abuse. so now im looking for a 4bt. anyways looking forward to the project! subscribed
 

KEENO

Adventurer
Correction

Copy on the D60 correction... 10 Bolt it is!

I assumed the 3/4 ton 'burb was the same as Military CUCV. You know what they say about making an assumption....

KEENO:)
 
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Spur

Adventurer
Oh yeah...

What are you doing with the 2wd once you pull the engine? I would be interested in it when you get to that stage.....

It's going to the scrap heap. If you really want it, send me a PM. I'm sure we could work something out. It's not in great shape, but you could probably find some parts to use.
 

jp0863

Observer
Copy on the D60 correction... 10 Bolt it is!

I assumed the 3/4 ton 'burb was the same as Military CUCV. You know what they say about making an assumption....

KEENO:)


Just for info, not for correction purposes, to inform everyone cuz it too me a while to figure this one out..
CUCV blazers (m1009) came with 10 bolts with 3.08 gears a gov loc in the rear and are considered a 3/4 ton truck.
The CUCV truck (m1008) has the d-60 and is considered a 5/4 ton truck, came with 4.56 gears and a detroit in the rear 14 bolt. B E E F !!

The nice thing is you can buy a 5/4 ton truck with the d60/14 bolt for about $1200 to $1500, rent a car trailer and pick it up. strip the cucv of all the good stuff (axles, hydro boost, etc) and sell the rest and make some money back. www.govliquidation.com is the place
 

Grim Reaper

Expedition Leader
Subscribed! I have evil ideas for a 3/4 ton burb that involves a sawzall and possible re-power. I have thought about converting my 88 454 2wd to 4wd but by the time I do the conversion I can buy a stock one.

Recently saw a 91 Dodge Cummings with a NV4500 and under 200K sell for $1800 locally. If I had the cash I would have got it. I read about somebody using a divorced NP205 and they were able to set it up so that the front and rear driveshafts came out the same length.

Look forward to a detailed report on what it takes to do the motor swap.
 

evldave

Expedition Trophy Winner
I began a national search for a ¾ ton 2500 Suburban with 4wd. Not many out there. I only found about 3 in the whole country, but one was in Round Rock. I drove up there today and paid $2,000 cash and drove it home. The drive-train is pretty worn out and so is the suspension, but the body is straight and relatively rust-free. There is a little surface rust on the roof, but that will get repainted.

How did you look for suburbans...I've been looking for similar as you (here in the PNW) and found a bunch...I know you've already found your donor, but if anyone else is thinking of searching for stuff like this, use www.crazedlist.org - I popped up a bunch of links for 'Suburban 3/4'

http://portland.craigslist.org/clc/cto/1246352403.html
http://portland.craigslist.org/mlt/cto/1246490767.html (6.2 DIESEL!)
http://seattle.craigslist.org/tac/cto/1246886927.html
 

dieselcruiserhead

16 Years on ExPo. Whoa!!
Very cool.. I did a NV4500 on my last round, it is defintely a good trans. You might look into a Ford ZF 6 speed trans, a little beefier and sometimes cheap to find used. I prefer it over the NV4500 and NV5600 both of which I own or have owned... Fordcummins.com makes an adapter. It would be a little more $$ but the low that you don't have to use everyday is nice. The NV4500 is basically a 3 speed with an over and underdrive aka awkward shifting, if it helps. But you get used to it.

Good luck with the conversion and don't be afraid to use some of the resources at www.4btswaps.com which is sort of diesel swapper central for both 4 and 6 cyl apps. Cheers, Andre
 

ntsqd

Heretic Car Camper
I wouldn't constrain yourself to "3/4t" even if that is what you want. In the late models that gets you the 14bsf which really isn't a whole lot better than the 1/2t's 10/12 bolt rear axle. Specifically it means that you would miss my 1/2t that was converted to 8 lug using '79 3/4t parts (14bff). As best as I can tell there is no difference in the 1/2t vs. 3/4t frames, so if 8 lug is what you're after it isn't that big of a deal to find a donor & swap the parts. I think it took me all of a morning to convert the front axle. The rear is a little more involved, but really only because of the heft of the rear parts. Still is really only a full day to complete such a conversion.
 

BBsound

Adventurer
I wouldn't constrain yourself to "3/4t" even if that is what you want. In the late models that gets you the 14bsf which really isn't a whole lot better than the 1/2t's 10/12 bolt rear axle. Specifically it means that you would miss my 1/2t that was converted to 8 lug using '79 3/4t parts (14bff). As best as I can tell there is no difference in the 1/2t vs. 3/4t frames, so if 8 lug is what you're after it isn't that big of a deal to find a donor & swap the parts. I think it took me all of a morning to convert the front axle. The rear is a little more involved, but really only because of the heft of the rear parts. Still is really only a full day to complete such a conversion.[/QUOT
 
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ntsqd

Heretic Car Camper
In the live axle body style, no. It would be a TH400. The 4L80E's came along sometime after the IFS trucks made the scene.
 

Grim Reaper

Expedition Leader
In the live axle body style, no. It would be a TH400. The 4L80E's came along sometime after the IFS trucks made the scene.

Actually the 4L80 made it into the 91 Burb and 91 Crew as the only year. As did power mirrors. It is the Holly grail for the 73-91 body style.

My 88 454 with the TH400 I can just nurse 11 out of it on the hwy. Guy that worked a couple doors down had a 91 454 with the 4l80 was able to squeek high 14's most of the time. if he kept the speed to 65mph on the hwy he said he has got mid 15's out of it. He sold it without telling me it was for sale. :(
 

motomech

Adventurer
1991 burbs and crews had all the cool stuff they put into the "GMT" trucks.
the 14bsf has huge 33 spline axles , huge bearings that dwarf a normal mans palm , and extra ground clearance over a full floater .

Run disc brakes and if you ever do actually manage to snap a shaft the axle will stay put .


I abuse the crap out of mine and i have yet to have a failure.
 
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ntsqd

Heretic Car Camper
snip....
Run disc brakes and if you ever do actually manage to snap a shaft the axle will stay put .
This sounds good, but experience has proven it not to work as expected. The wheel & tire still came off. Tore up the rotor and caliper in the process.
 

wikid

Adventurer
Interesting build. I love different. Your job ( since you are having a fab shop do the heavy work) will be to get your camera to the fab shop whenever you can, so we can see the progress, at all the different stages. Or maybe recruit the guys at the fab shop to photograph the complete process . I did complete documention of my camera mod and am glad I did.
This should be fun to watch
thanks
Don
 

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