1997 K2500 Suburban Cummins Install/Conversion

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SmittySS

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So I purchased a rust free 1997 K2500 Suburban with a rod knocked 7.4L from Arizona. I think I got a pretty good deal on it, and had it shipped to me here in SE Michigan.
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My 1996 K2500 Suburban 7.4L has served us very well, but being a Michigan truck... it looks just like you would expect of a now 22 year old Michigan truck with 200K on the odometer. It's been such a good machine, I decided to get a clean one from out west and put a fresh new Big Block in it.

The plan was to build a 496ci stroker. Since it needed a crank kit anyway, why not make it a stroker!
After running a few different versions of it on "Desktop Dyno" I picked out a cam I thought I'd go with, and was pretty happy with the numbers I was seeing. Not that I put a ton of stock in what that program calculates, but I figured it might be close: About 510hp and 623ft.lbs.

It was somewhere around this time I ended up watching a video online of a Cummins swap from a late model Ram 2500 (95) into an early D250 (73).

I was amazed at the rear wheel power it made when they put it on a dyno: 293hp and 755ft.lbs... and still getting over 20MPG!

I had never considered do a swap like this... I like my Chevy V8's! The Big Block in my 96 sounds so good cruisin' down the highway...
But if you keep clicking on Cummins swap videos on youtube... the GMT400 Cummins swaps start showing up.
I got to thinking (and that's often not good :p), and figured if I could find a good deal on some of the things I needed to do the conversion, it would be worth it.

Enter the purchase of this 1992 5.9 12 Valve Cummins:
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After looking at several for sale on CL and Facebook pages for sale, I decided to purchase this one for a couple of reasons.
One, it was said to be only 120k on the engine, and the other was it had a TH400 bolted to it, meaning it had the GM trans adapter bolted to it.
I talked to the guy selling it, he told me me he had installed it in a 78 Chevy pick up, but after having a heart attack, gave up on some of the projects he had going at the time. This was back in 2013. Someone bought the truck but didn't want the engine and it got put in a shed. He told me he bought the 1992 Ram from and older guy, it had be t-boned on the passenger side, but could still be driven. He told me he searched high and low for the GM adapter out of a bread truck to hook the TH400 to the Cummins.

I thought I would be able to use this adapter for my swap in my Suburban... but I leaning toward not using it on this swap.
I was not aware that the bread trucks had an 8 degree lean built into the GM auto adapters:
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Also I have read that the "wave ring" that attaches the Torque Converter to the Flywheel is good for about 200hp...

So, I'm going to have to sell some things... A TH400, a GM Cummins (bread truck) Adapter, a 96 454 Block and Heads, and a few other things... LOL.
Then I'll purchase one of the aftermarket GM Auto Trans to Cummins Adapters.

But for now, here's the 5.9 12 Valve Rarin' to Go!

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Blessings!
Smitty
 
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SmittySS

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you gonna box the frame? i'll be watching your progress....cool
I haven't thought much about boxing the frame. I'll surely take a look at that while I have it up on the hoist doing other work to it.
Do you know of any specific areas which may need attention?

Smitty
 

shovelbill

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I haven't thought much about boxing the frame. I'll surely take a look at that while I have it up on the hoist doing other work to it.
Do you know of any specific areas which may need attention?

Smitty

not on these trucks......i know of 2 guys that decided to box the frames on '73-'91 suburbans......i guess the frames are thinner from those years....especially around the steering box area.

here's an interesting site.
https://www.dieselconversion.com/co...-1998-12-valve.html?options=cart#!prettyPhoto
 

Lanny

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With the added weight of the Cummins, around 1250 lbs dressed, I would at least box the front. You wont be sad with a stiffer frame either. Helps with body gaps and comfort when loaded.
 
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