1980 12 valve swap

[1980iowaram]

hey guys i have come across a 1991 cummins d350. with the five speed getrag. non intercooled. 250000 not to bad but i really cant stand to have a two wheel drive truck so i am considering my options. i have a 1980 w200 with a 318 and a four speed. adn a little tired. dana 60s front and rear. i have heard the frame is the same for the 91 adn the 80 but am i hearing right. i would probably have to swap dashes from truck to truck. how hard is it to get all the motor mounts and trany mounts. how much fabrication is in volved. also i would have to make the tranny mount to my tcase. how hard is this and how much would it cost other than labor. i can weld adn do some fabricating. on a scale of 1 t0 10 how hard is this. thanks for your help.

[MoparNorm]

A couple of guys here have knowledge of those trucks. If the frame is the same the suspension will still need help, the 5.9 is a big chunk and needs to have a stout platform under it.
Good Luck!

[JimmieD]

It would be easier by far to simpy [?] install the Cummins engine in the 1980 4 X 4. You surely need stronger front springs as the Cummins weighs around 550 lbs more. A minimum upgrade would be 250 lbs per side increase on spring rate, and I suggest adding a a bit more, like 350 lbs increase per side?

The Getrag is longer than your NP435 so you'll have to deal with that. Are you a married transfer case or divorced? Should be an NP205, right? Either way it's a driveline cut and paste. You'll have to look at the crossmember also, to see what the Getrag uses on the other truck and either copy or swap.

Others can give more info, but there's issues with the offset of drivelines and T-case and related clearance, plus you need to clear the steering box which can be tight. If you have good prior fabrication skills it's just another job only different. If you don't then it can be a real challenge. One thing you want is to plan the job and have all the possible questions answered before you even twist a wrench. Nothing worse than a project that never gets finished.

On a scale of 1-10 for difficulty rating, with changing clutches rated as a 1, see the link for a 10:

http://www.bankspower.com/Leno-tankCar1.cfm

From those references your project could be somewhere beteen a 5 and a 9, depending...

[1980iowaram]

whats the diffrence between a divorced and a married tcase. and yes it id the np205. the front springs all ready have a add a leaf in them. do you suggest more custom springs to add the the pack.

[MoparNorm]

Well, divorce is when two people separate and ...uh never mind...ha!ha!
Married cases are mated to the transmission directly without a drive line.
Divorced cases have a short drive line between the the two. Now, why they call that shaft the drive line and not the mother-in-law, I have no idea......= )

[JimmieD]

As I recall, dimly, the 6BT weighs around 550-600 lbs more than the engine coming out of your 4WD. I have no idea what rating your add-a-leaf is but I feel confident it's 300 lbs per side. My preference is to have new custom spring packs built by Eaton Detroit Spring, at around $500 complete, any weight you choose.

On a diesel swap you will never regret building heavier, stouter, meaner. I added 250lbs per side on my new Eaton Detroit Spring packs and see now that 300 would have been just a bit better, 325 maybe better yet. That was for a 4Bt into a 1/2 ton 2X truck. Depends on how you want the truck to ride but afterall it isn't a Buick.

As for the mother-in-shaft, I have no idea either. I do know that if you don't pay attention to them, keeping things well lubed, they can cause lots of problems... :~ 0

[Keith in CO]

Front axle for a 6BT

[QUOTE=1980iowaram; i have a 1980 w200 with a 318 and a four speed. dana 60s front and rear. [/QUOTE]

I could be wrong (it has happened a time or two ;) but your W200 should not have a D60 in the front unless someone has done a upgrade/swap from a one ton. Also, as far as I know, Dodge used either a front Dana 60 or 61 in all CTD equiped 3/4 ton 4x4 trucks.

[1980iowaram]

the guy that i bought it from was the original owner of my truck and he said it was a heavy duty version. and yes i have checked both front and rear are dana 60s.