1st Generation Dodge Cummins 89-93 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with Rotary Injection Pumps

On my way to 12v swapping

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Old 10-11-2015, 06:57 AM
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Default On my way to 12v swapping

Okay so first let me start, I'm new, my first post, so if I'm in the wrong area let me know where I can go . Here's what I'm up to...

1979 dodge 1/2 ton 2wd swb
12v motor
47rh transmission

So here's what I got to start with, and as you can see I'm going to try and do a conversion. Shouldn't be that hard I wouldn't think but beings 79 wasn't meant for cummins yet I may have issues but that's why I'm here. So my questions will start as:

What engine mounts should I use?
How should I mount the tranny?
What springs should I use up front?
What rear end would you all go with? (I'm planning on ford 9" for racing purposes)
Any certain areas of the frame I should box in or "beef up" in some way.

Thanks for any help guys
 
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Old 10-12-2015, 04:20 PM
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Originally Posted by Kentucky_cummins
Okay so first let me start, I'm new, my first post, so if I'm in the wrong area let me know where I can go . Here's what I'm up to...

1979 dodge 1/2 ton 2wd swb
12v motor
47rh transmission

So here's what I got to start with, and as you can see I'm going to try and do a conversion. Shouldn't be that hard I wouldn't think but beings 79 wasn't meant for cummins yet I may have issues but that's why I'm here. So my questions will start as:

What engine mounts should I use?
How should I mount the tranny?
What springs should I use up front?
What rear end would you all go with? (I'm planning on ford 9" for racing purposes)
Any certain areas of the frame I should box in or "beef up" in some way.

Thanks for any help guys
I'm most of the way thru putting all the 8-lug stuff and Dana 70 from the '90 cummins donor into my 2wd Ramcharger. The cummins mounts land just the same on the 1/2 ton crossmember.

The center-link on the 2wd cummins trucks is dropped for oil pan clearance. You can make it work on the low-gvw suspension if you ream the knuckles larger. (TREs are all bigger)

The cummins-rated coil springs are longer and won't fit with the low-gvw arms. Either cut the coils, or run van arms because they have a deeper pocket.

For the frame, I'm leaving it as-is. The RC is short, and the body itself adds rigidity. I did have a spare steering box brace which I added.
 

Last edited by u2slow; 10-12-2015 at 04:25 PM.
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Old 10-12-2015, 05:55 PM
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Well I'm glad the engine swap itself won't be a big deal. As far as springs, I took the stock springs out of my 2012 3/4 ton, so those will work if I cut some coils off? Any idea on a dodge rear end that will hold just as well or better for a drag truck? I was thinking of boxing the frame at least in some areas to help. I don't guess my body will hold it as well since mine is seperated
 
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Old 10-12-2015, 06:50 PM
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No idea on 2012 coils. The '94-95ish 4wd coils I have are too large a diameter to fit a 1stgen 2wd.

The Dodge 8.75" or 9.25" should hold. Ford 9" or Dana 60 is always a good choice. Make sure you can get the fairly tall gearing you want for the cummins in the axle you choose.
 
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Old 10-12-2015, 06:58 PM
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so if I was to swap arms to van arms which would I want so everything would fit? I would think the 8.75 would shatter that's what is in the 1/2 ton stock. Maybe a Dana 60 but I'd probably want to have it cut and I don't know how much that would be.
 
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Old 10-12-2015, 07:14 PM
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I'm thinking of the same van arms guys use to lower their trucks...
How to lower the front of your 1972-1993 Dodge Pickup - DodgeTalk : Dodge Car Forums, Dodge Truck Forums and Ram Forums

The 8.75 is very strong. Some say as strong as the 9".

5-lug Dana 60s are rare, 30-spline, and command a heavy price. I would look for an 80's F250 semi-floater (Dana 60 or 10.25"; both 8-lug 35 spline) .... redrill the bolt pattern, and roll your own brakes. Both usually come with 3.54 - 4.10 gears, but 3.31 exists, and even 3.07 for the 10.25".

EDIT: My buddy is building a '73 Chev C10 with cummmins/nv4500. He went with a 9", 3.00 gears, and 35 spline shafts on a Yukon center section.
 

Last edited by u2slow; 10-12-2015 at 07:26 PM.




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