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73-87 Chevy _ GMC Trucks => Diesel Engine Discussion => Engine/Drivetrain => Cummins Swaps => Topic started by: reed85 on November 27, 2016, 01:03:39 AM

Title: time for cummins swap
Post by: reed85 on November 27, 2016, 01:03:39 AM
Well guys ive been driving my 85 scottsdale c30 for about a year an a half my 350 finaly gave out on my so ive been wanting to do a cummins swap for more power and the ability to run highway miles. Im going to stay 2 wheel drive and going standard transmission. Im looking around some junk yards to try and find parts while im looking ive started to pull the 350 and turbo400 and get the truck ready any tips on body or frame mods that any one has done or and problems with goin from auto to manual transmission
Title: Re: time for cummins swap
Post by: 1967KaiserM715 on November 27, 2016, 06:08:58 AM
Chances are your tunnel hump won't be tall enough to clear a manual transmission. Getting hydraulic pedals and bellhousing shouldn't be too difficult. Beyond that I won't be able to help much.


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Title: Re: time for cummins swap
Post by: reed85 on November 27, 2016, 08:01:34 AM
O yea i did for get about that thank you kaiser.
I did read a jeeps cluch petal and mastercylinder works great with the dodge cluch slave cylinder
Title: Re: time for cummins swap
Post by: Irish_Alley on November 27, 2016, 01:30:53 PM
moved to the right section. but we'll get you pointed in the right direction
Title: Re: time for cummins swap
Post by: hatzie on November 27, 2016, 03:07:06 PM
1985 was the first year of the hydraulic clutch setup so the firewall should already be dimpled for it.  You'll need to carefully drill the holes with a Unibit.  Measure four times and drill once...  :P ;) starting with a tiny pilot hole.

You may need a bolt-in high transmission hump or a mild body lift to clear the NV4500 with the trans tunnel.

An early 1990's 2wd Cummins Dodge NV4500 should have a gear drive speedometer setup.  AND YES...  You can use the Dodge 2wd NV4500.  In this case it's probably preferred.  The GM T400 chassis NV4500 only has VSS Speedometer parts not gear drive.  The Cummins bellhousing to engine bolt pattern is on the Dodge bells GM is setup to mate with GM Corporate standard bellhousing to engine bolt patterns.

You'll need a universal joint to mate with the transmission output yoke at the transmission end of your driveshaft, the right length driveshaft (probably custom length but not necessarily), and you'll need to massage the transmission crossmember for the new mount.

That's about all the help I'll be.  Other folks with more specifics about motor mounts, belt driven accessories, and firewall clearances among other considerations will jump in.

You may need to get heavier front coil springs to carry the much beefier Cummins...  There are other folks that have done this swap that can tell you more on this and other finer points.
Title: Re: time for cummins swap
Post by: Irish_Alley on November 27, 2016, 03:17:55 PM
ok, bajaburban will be able to tell you exactly what you need to do he does these swapps weekly in his shop. cheapest way if you dont have any parts for the gm cummins is finding one with thats mated to a nv4500 or getrag. are you planing on a 24v or 12v or what? what power do you plan on making?

baja also makes motor mounts for this swap theres two ways you can do it. one is the crossmember/motor mount that he makes or the way i did with with using gm motor mounts in the stock location but you have to push the trans back 3" to do this. if you go with body lift to clear the trans you wont have to cut into the firewall and you have to have a new driveshaft anyway so it might be the cheaper way anyway. but idk about the 2wd front crossmember hitting the oil pan, baja will be able to tell you about that
Title: Re: time for cummins swap
Post by: reed85 on November 28, 2016, 07:53:18 AM
Ive thought about a 2inch lift on the cab i have a western hauler bed ( i dont even wantvto think of removing ) and the way my tool box is blocks half my rear window it i pick the cab up ill be able to see and hope it helps with the clearance.  Im wanting the 24v cause every one wants the 12v and i may find a 24v easier i will be wanting the Ppump. I am going to go look at the fire wall for the cluch pmounts thank all of u guys