Well as some of you know im new here and have tons of more ideas for my old girl. Yes i refer to my truck as a girl. Well the ultimate makeover i want to do is go from a v8 to a cummins. the only problem i have with this is im not sure what will all have to be done to make the conversion I already have a 1991 inline 6 12v cummins turbo with 78,000 original miles on it. but that's all i have.my? is what else do i need for the conversion besides the transmission. all posts will be thoroughly read and used.

 

If you want to put the Cummins into a gasser frame -
you'll need at a minimum a new front end...

The gasser weighs 1/2 what the Cummins does -
Unless you've got a 440 in there now, then the 440 weighs 2/3 what the Cummins does.

A trans is a must, the gasser trans can't take the torque at low rpms and it will shift at too high rpms for the Cummins.

The rest of the driveline - u-joints, driveshaft, diff, rear axle all need to be upgraded to handle the torque.

BUT - the good news is :
it has been done.

 

ok so I know this will be in kinda a bit of detail but for bare min. can any one tell me what parts i will need. Im not looking for power right now I just want to do the conversion then later down the road start building the motor

 

I hope you are starting out with a 3/4 or 1 ton and the only gasser auto tranny that will bolt to a 5.9 would be from a newer V-10 truck .

If your truck has a very nice body look for an ugly cummins truck and swap cab + box it would be much easyer, faster, and cheaper.

 

its a stock 1990 W250.

 

What's the difference between the 3 speed in my '90 and the ones that were behind gas engines? I've always wondered that.

I have a 1971 RV on a Dodge chassis that I think is technically rated at a lower GVWR but is a "step above" a 1-ton chassis. It has a 400ci "industrial" gasser and the trans looks practically identical except for the tail housing, which has a parking brake, etc. The u-joints and driveshaft are the same size as on the '90 and the rear end looks extremely similar.

I had just assumed that the trans adapter plate on the Cummins was meant to bolt it up to a regular, gas-engine 727.

 

There's no reason you can't do a Cummins swap into a half-ton. Just don't use it like a 3/4 ton and it will be a nice little hot rod.

 

To the original poster: I think you will be spending way more time, aggravation, and possible money than just buying a diesel W250.

Sell the Cummins and realistically you'll fetch $800-$1000 for it. There are so many Cummins for sale that are more than that that don't move unless you find the right person at the right time, or it's a 215hp P-pump model.

Sell you gasser, I'm not sure of the condition but any 3/4 ton running truck that will get inspection is worth at least $1000-$1500 in my book, and more likely $2000-$3000 if it's nice.

Save the money you would have invested in the swap. I'm guessing $1000 or so for the tranny/transfer case, $200-300 in yokes/ and drive shaft shortening/lengthening, etc. An engine harness would usually be utilized and a used one is $100 or so... etc

For $5,000, you can get a pretty good W250 with a Cummins already in it. And occasionally you get a real good one for less.

If you wanted to swap the Cummins in a truck that never HAD the Cummins, I understand that swap more. All that time and aggravation searching for parts (since you don't have a wrecked Dodge with a cummins, you only have the engine itself) just would not be worth it in my opinion. But to each their own.

 

^^^ i agree. and if you just buy one, even if it needs minor work to be road worthy. down time will be much less than building one from pretty much scratch. also if you can find a truck you like and have money left over from the stuff you sell you can buy upgrades for the new truck

 

It will be probably cheaper, and will definitely easier to just hold out and buy one with a diesel already in it.

 

simple: rip out V8

get cummins engine mount drop engine and tranny in, make new tranny cross member and new driveshaft and done..

these are very easy to drop into any dodge frame..

sure it takes time but it will go pretty much right in with out to many issues.