'98 12Vinto a '00 chevy 1-Ton dually

chvycmnslvr68 · Dec 9, 2012

I am buying a 2000 model chevy dually service truck and it currently has a 350 Vortec in it with an NV4500 five speed tranny ...

My questions are related to installing a '98 12V Cummins into the '00 chevy truck .... has anyone done one of these conversions and can I get the input shaft and bell housing for and earlier dodge to bolt right together with this engine and tranny combo .... Also on the conversions of this type that I have looked at on other forums they have used electric fans instead of the original cummins fan due to engine compartment room ... I think that I can set the engine and trans ass'y a bit further back in the engine compartmant so as enable me to ust the mechanical fan that comes on the Cummins engine .... does anyone have any experience with a similar swap ...
I was able to do it this way with my '91 CC dually in my avatar photo but have no experienc with the newer chevy's ...

Any help or input will be greatly appreciated ...

The Warden · Dec 9, 2012

No direct info on this since I don't know beans about the Chevy chassis, however, I see one potential concern.

chvycmnslvr68 said:
Also on the conversions of this type that I have looked at on other forums they have used electric fans instead of the original cummins fan due to engine compartment room ... I think that I can set the engine and trans ass'y a bit further back in the engine compartmant so as enable me to ust the mechanical fan that comes on the Cummins engine .... does anyone have any experience with a similar swap ...

One thing to keep in mind is clearance for the valve covers. You need to be able to remove all six valve covers on the 12 valve in order to do routine valve adjustments...I don't know how much of an issue that will be with the Chevy chassis since I don't know how the firewall's shaped, but it is something to be concerned about. Swapping a 24 valve in would eliminate that concern, although I don't know if that's a route you're willing to go...

tanman_2006 · Dec 10, 2012

Is this a 10 lug 3500hd or 8 lug 3500? 2wd or 4wd? If it is 10 lug cab and chassis then the cummins will nearly install itself, 2wd 3500 its still pretty easy, 4x4 means oil pan mod and BFH on the firewall.

As for the tranny, 96 and newer GM NV4500 uses the same bellhousin to tranny bolt pattern as cummins and input shafts are interchangeable. You will be fine if you stay under 400hp, the gm nv 4500 is lighter duty than the cummins. It is rated 50-100hp less depending on yrs, the gears and synchros are the same it think it is the case design and input that differs.

jhnlennon · Dec 15, 2012

The Warden said:
No direct info on this since I don't know beans about the Chevy chassis, however, I see one potential concern.

One thing to keep in mind is clearance for the valve covers. You need to be able to remove all six valve covers on the 12 valve in order to do routine valve adjustments...I don't know how much of an issue that will be with the Chevy chassis since I don't know how the firewall's shaped, but it is something to be concerned about. Swapping a 24 valve in would eliminate that concern, although I don't know if that's a route you're willing to go...

24 valve also had adjustable valves train, although the service interval was much longer than the 12 valve...

chvycmnslvr68 · Dec 15, 2012

tanman_2006 said:
Is this a 10 lug 3500hd or 8 lug 3500? 2wd or 4wd? If it is 10 lug cab and chassis then the cummins will nearly install itself, 2wd 3500 its still pretty easy, 4x4 means oil pan mod and BFH on the firewall.

As for the tranny, 96 and newer GM NV4500 uses the same bellhousin to tranny bolt pattern as cummins and input shafts are interchangeable. You will be fine if you stay under 400hp, the gm nv 4500 is lighter duty than the cummins. It is rated 50-100hp less depending on yrs, the gears and synchros are the same it think it is the case design and input that differs.

I took some measurements today after I got my truck paid off and took possession of it ....I will have about 1.5 Inches between the cummins engine fan, and the radiator core, without modifyng the firewall at all, and there will be plenty of room to get the rear valve covers off as well ... even better than the dodges had in them .... From what I can see after measuring ... the only mod's I will have to make will be to the frame at the front of the truck .... and then I will have to customize the steering linkeages ... to fit with the frame mods ... all in all it looks like it will be a fairly simple swap ... and once the frame mod's are done to fit the a/c compressor ... then all I have to do is to fit the '98 charge air cooler into the Chevy grill and then reinstall the a/c condensor ...
But as far as the trans goes .. I talked to a transmission expert and he said that the Chevy nv4500 from 97 to 02 are the same tranny as the 94 to 02 dodge except for the clutch spline size .. so all I have to do is to buy the dodge input shaft and bell housing ... and Walla ... it will all bolt together ...

I may remount the a/c compressor a bit higher on the cummins rather than doing the frame mods .. will have to wait to see how things look with the engine henging in there ...

I will begin pullling out the vortec 350 tommorrow and will try to take as many pics as possible ...

tanman_2006 · Dec 17, 2012

Yes sir 97 (96 was the change over yr) and later nv4500s are the same tranny mounting flange and the input is the only difference in bolting them to a dodge. That doesn't change the fact that the 5th gear IS different and has a lower hp rating. I've rebuilt a few and they don't cross over.

What model of truck do you have? Sounds like an hour model with how easy it fits.

Things get tight when you try to add the intercooler. The one on my 93 barely fits with a 24v innercooler

chvycmnslvr68 · Dec 23, 2012

Well I finaly got the vortec pulled out and stuck the cummins in the truck to check for fit ... the RH frame rail has to be modified ... where the frame swells toward the middle to mount the Idler arm for the steering .. I simply cut a straight line directly above the Idler arm mounting bracket and made a cut out in the top half of the frame about four inches in width ... and about 11.5 in length I then laid a piece of angle iron into the hole and began fitting it back into shape with the 90 degree notch .... It turned out pretty good ... I will try to get some pics posted as soon as I can ... I then hammered the body seam where the floor meets the firewall back and made it flat and smooth... I will have to adjust the floorboard a bit more so that the bell housing will clear ... I am going to have to move the trans back approximately 5.5 inches so the front half of the driveline will have to be shortened ... but at least I dont have to make any firewall modifications .. there is a mess of air ducting on the inside of the cab directly behind the firewall so that would become quite a mess ...
Anyway .. after one full day of work I feel pretty good about the way things are going ... hopefully next weekend I will have my new bell housing and tranny parts ... so I can get the motor mounts built and I hope to have the charge air cooler installed as well ... I am going to remove the airconditioner condensor and install it where where that came out with the inlets upward .. I wil then have to turn my battery boxes 90 degrees to clear the top mount air tubes .. It should make almost a straight shot for the air tubes though ... I will also have to cut about four inches out of my intake inlet and rotate it upward about 45 degrees and run my piping directly above the injector lines .. that way i can keep my antilock brake system intact ... otherwise I would have to relocate it ... and there isnt much room on the driverside of the engine compartment... I willl later add a a/c condensor back into the front side of the radiator between the air cooler and the radiator .. I think there will be just enough room for one of those aftermarket jobs that are only 1" thick to ziptie to the frontside of the radiator ... and still maintain enough square inches of cooling to have good cold a/c ...
Will update more after next weekend ...

tanman_2006 · Dec 24, 2012

Could you please share some info on the truck? Service truck makes me think 3500hd but I never had to modify the floor or firewall on the one I did. I've done a 4x4 and took quite a bit of work and I had to set the engine back in the frame to get the innercooler, ac condenser, and mechanical fan set up to fit. When. I set it back 2-3" it took more mods to the firewall and floor pan.

chvycmnslvr68 · Dec 25, 2012

tanman_2006 said:
Could you please share some info on the truck? Service truck makes me think 3500hd but I never had to modify the floor or firewall on the one I did. I've done a 4x4 and took quite a bit of work and I had to set the engine back in the frame to get the innercooler, ac condenser, and mechanical fan set up to fit. When. I set it back 2-3" it took more mods to the firewall and floor pan.

Hey tanman ... what questions do you have specificly ... I thaought my description of things thus far were pretty well laid out ... and yes it is a 3500 2x6 reg cab Chevy .... I notched the frame to clear the a/c compressor and then hung the motor back in the engine compartment ... clear back to the firewall ... I then slid the radiator support back in place and lined up the bolt holes and then sat the radiator back into place ... I had apprxly 2.5 inches between the fan and the radeiator core ... and the shruod will be pretty well centered over the fan I just will have to cut the length of the shroud down about 5" to not hit the belt and other engine parts ...

tanman_2006 · Dec 25, 2012

10 lug or 8 lug?

Have you fitted the intercooler? I didn't have room behind my grill for it with out moving my support back and trimming the back side of the grill.

chvycmnslvr68 · Jan 5, 2013