question about 12v cummins swap....

[nuzzi]

Im having a hard time finding much info on these trucks, can anyone point me in the right direction about engine swaps? will a 12v cummins bolt up to the stock 4spd? if not are there adapters available? do any V8 engines bolt up? thanks sorry for the long list, im just trying to get a plan going.

[Desoto61]

Going back through this section and the conversion/diesel sections will yeild most of the answers you are looking for.

The short answer is that the 6 cylinder Cummins will not fit in these trucks without a LOT of modification. They are too long to fit in the stock engine bay without cutting into the cab or lengthening the hood.

Most who want diesel power go with the smaller 4BT, which is a much better fit size and power wise for the stock drivetrain.

As for V8 power plenty have gone that route. There used to be a kit available from Ugly Truckling. Pices of that kit can still be purchasec but I don't think the whole thing is available any more. It's an easier and far cheaper conversion than a diesel.

Gas engines will more easily bolt up to the stock transmission but there's little reason to do so. If you're taking the time effort and money to run a more modern and more powerful engine a newer transmission, usually with OD is a relitively easy and worthwhile upgrade. Especially if you ever want to go faster than 55 mph.

[Alxj64]

But don't forget about the brakes! With one modification, usually another follows. If you go faster, you need to be able to stop. If you can stop you might want to be able to steer.

Its true that the 12V 6 cyl simply doesn't fit well. However, the 4bt isn't the only diesel that may fit. I was on the fence, and almost hopped it, for installing a 3-53T Detroit diesel. Its a little more rod-ish as its very loud but would be very unique. There is a forum called 4btswaps.com. Maybe dig around there for a bit and see if there is anything that strikes your fancy. There is a thread with a 6 cyl 12V in it, but the builder said that in retro-spect, he wished he had gone a different route.

[nuzzi]

thanks guys, I found the swap section. I know everyone hates the new guy so ill do my best to search the site before posting repetative questions....I thought the legacy conversion used the 12v so i didnt think that much modification was neccessary. V8 is probably a better way to go anyway, im thinking a 360 or 440 setup with newer drivetrain would be a good start.

[Clint Dixon]

thanks guys, I found the swap section. I know everyone hates the new guy so ill do my best to search the site before posting repetative questions....I thought the legacy conversion used the 12v so i didnt think that much modification was neccessary. V8 is probably a better way to go anyway, im thinking a 360 or 440 setup with newer drivetrain would be a good start.

I too have visited those sites where "everyone hates the new guy." I think you will find that THIS site is NOT one of those.

Welcome!

[Desoto61]

But don't forget about the brakes! With one modification, usually another follows. If you go faster, you need to be able to stop. If you can stop you might want to be able to steer.

Axles can easily be the most expensive part of one of these builds. The stock ones will cost quite a bit to rebuild and convert, possibly more than your drive train setup. You may get away cheaper changing to something else, though that brings its own issues.

Not trying to scare you off, just want to point out how slippery the slope gets before you decide to join us in the fall.

[nuzzi]

thanks for the warning, but im fully aware of what im getting into. as of now im thinking a fuel injected magnum 360 swap with a 4 or 5 spd, a D60 front axle, havent decided the best rear end yet. just have to figure out what tc i can use with what tranny to get a pass side drop. i have no issues with modifying spring perches ect, 2.5 ton rockwells are also an option. for now however, it will stay stock.

[Ggg6]

I have a 453N swapped into my 57 W300. I used a Clark transmission and upgraded to 4 wheel disc brakes. I was a heavy diesel mechanic for a long time so diesels are in my blood so to speak. I have also swapped a 4bt into a Jeep TJ and I'm very happy with both swaps. I have personally seen about six examples of the 6bt being swapped into a power wagon and the flat fender versions are too short in the engine compartment. Even my own with the 453 is about 5" too short.

[Alxj64]

To the original poster, 2.5 ton rocks will probably keep you off of the highway. I know that it will where I live, and there are lots of really big trucks around here. Everyone is correct that its expensive and time consuming, but at least with this kind of stuff, you usually have something to show for your time and efforts. Theres just something cool about an old truck with new running gear, but I prefer to try and hide the look of the new running gear as much as possible.

I have a 453N swapped into my 57 W300. I used a Clark transmission and upgraded to 4 wheel disc brakes.

Do you have any videos of that thing running? I almost went with a 3-53 or 4-53 for my Carryall before deciding on the Common Rail 3.9 Cummins.

[Ggg6]

I don't have any video of it running, but I do have some pictures of it on 4btswaps, my username over there is Ggg. I have a build thread over there for my 4bt/Jeep TJ as well.
My opinion on the axles is for street driving/mild off road use and tire size up to 40"ish the stock axles are fine for any of the engines mentioned so far in this thread. The 9 5/8 axle is a fairly strong unit, its weakness is the shafts and chrome molly shafts can be made solving this issue. Rockwell axles are not really needed unless you are well above 50" tires, super heavy, or rock racing with a big block. The Rockwell gearing sucks for street use.

[nuzzi]

I agree the rockwells are overkill it was just a thought, I wouldnt use them haha. Unimog axles on the other hand would be killer, and I dont care if it tops out at 50mph. I hate to steer away from Dodge parts but what do you think about a V8 diesel swap? Chevy or Ford obviously. Gasp I know, but aside from the weight i would think they would fit since V8 gas swaps are common. Any thoughts?

[Ggg6]

The Powerstroke is the same weight as a 6bt around 1100 pounds wet, and a Duramax is a tad lighter. The V8 diesels are a little longer than a big block and about as wide as a 426 hemi. So they are a bit bigger than a modern day gas V8. The V8 diesels tend to operate at a higher rpm range than do the inline engines the PSD 6.0 revs higher than a 7.3L. The V8 diesels are mostly electronic controlled so you will have that issue to work out. There are a few old V8 diesels that are mechanical but they are not power houses like the electronic engines. The Duramax has the best potential for making easy power with plug and play programmers compared to the Fords.

[nuzzi]

thanks, I think if i do any engine swap ill do a 5.9 gas setup. The more i think about it though Ill probably keep it stock. After all thats what makes it what it is, and I really like flatheads for some reason.

[Jerry Henry]

I think that's smart, especially if the engine runs strong and quiet. You can always convert later, or find another truck to do the conversion. It really does seem the best diesel is the 3.9BT, as Paul in NY has done so many times.