I'm Cummins swapping a '74 Duster, thought I'd share the progress.

[85glht]

This car pictured here was a 1960 Chrysler 300F that a friend of mine owned (RIP). At its peak it had a 500CI Kieth Black 440 based aluminum engine. He outfitted it with a Lenco 5 speed transmission and many other mods to try and keep it alive. The rear end was the weak link. Before it was dismantled for an “upgrade” it ran a best of 10.xx @ 13x m.p.h. (Sorry, I can’t remember all the details. The car weighed 4000 lbs. My point is, almost anything is possible.
Back to your regularly scheduled programming.

 

[72bluNblu]

No one is arguing the fact that the guy can do whatever he wants with his car. I mean come on.

To your point - people don’t generally modify unibody cars to such an extent. Nor do they put 1,500 lb drivetrains in 3,400lb. cars. When you start going beyond stuff like frame connectors and torque boxes you better be a really good fabricator or you take it to a chassis shop and have **** done right and safely. Problem is the OP admits that he does not know what he is doing. That does not sound like a recipe for success.

Frankenstein is a cautionary tale.

You've said this "1,500 lb drivetrains in 3,400lb. car" thing twice now, so I'm assuming you don't understand that your math is wrong. A '74 Duster weighs ~3,400 lbs with its drivetrain. He's not adding 1,500 lbs to the car.

That 3,400 lbs is with a fully dressed small block, which means you need to be subtracting at least 600 lbs from that figure, because we're talking about a fully dressed, all iron, factory 360 right? Maybe more if it's an AC car? And then you need to subtract about 120 lbs for the transmission. So what, 720 lbs worth of drivetrain?

And as I said earlier, the dry weight on a '67 426 street hemi was ~840 lbs. So, they put those in A-bodies right? With A833's? So, now we're subtracting 960 lbs if you're comparing an A-body with an early street hemi to a 5.9 Cummins?

The op is probably gonna be adding 700 or 800 lbs to the car vs say an early 426 street hemi or all iron big block, which no one would give him any grief at all over. Yes, that's a lot, but it's not outside of the realm of strengthening the chassis.

And we haven't even addressed payload, because I'm sure somewhere there's a spec for what the maximum payload is with 4 passengers and a trunk full of junk. So even adding 800 lbs probably isn't going more than a few hundred lbs over what Ma Mopar figured that Duster could haul fully loaded with passengers. I dunno about you guys, but I've never had 4 people in my Duster at the same time, so that wouldn't even be a thing.

And it's a '74, so there's a good 100 lbs worth of shock bumpers he can get rid of.

And right, it's a '74, which no one gives a crap about anyway. At least that's what everyone says when you want to restore one right? That '74 won't be worth anything and you should get a '70-72? Definitely heard that before here.

For @Daniel Garcia, the big question I have is why the G56 transmission? Since your car is still going to be substantially lighter than a 2500 truck, and won't be towing or hauling, I bet you could use a smaller transmission than that which would definitely make your tunnel and crossmember fabrication work easier. Unless you're planning on towing 10k lbs with your Duster too...

 

[Rug_Trucker]

Easy to get 1000+ftlbs of torque out of a Cummins.

 

[Brooks James]

Yowzzir, the further out of the box, the better

 

[cosgig]

I like it. I think it's cool. Go for it.

I agree, I want to see this done, it should be a really fun project, and will test his mad fab skillz to the max!

 

[DumpsterFire]

I don't see a problem with calling out ill-advised buffoonery. Maybe no one around him has questioned this idea until now. The OP does seem to be able to handle the criticism just fine though.

Posting things online is obviously a choice and it should go without saying that if/when you put yourself out there in a public forum for all to see you have to be prepared to accept differing opinions on whatever it is you’re doing. Can't always expect to get 100% validation on everything, especially for doing something that makes zero sense.

To be clear, he's getting negative feedback from some of us because he is trying to do something that defies logic and will most likely bury another Mopar. Most people here care enough about these cars to not want to see one willingly get destroyed for a pointless exercise.

I'm not sure how anyone could be in favor of this project but what do I know. I'll just stay inside the box.

Everyone shoving a cummins into silly things, knows its silly

 

[Daniel Garcia]

To address some concerns that everyone seems to have. I in general do not know what I'm doing, I do know how do all of the engine work, suspension, brakes, plumbing etc, but specifically with fabrication etc., no idea. I do however understand general concepts. I have an understanding of welding and techniques, however no practice. So I'll just weld scrap metal together, until I can get a good result that I would feel confident fabricating cross members, frame ties, etc. to actually install in the car. That is the inherent nature of being a car guy, right? Even if you don't have a formal education, tinker until you figure it out, especially now with the internet, there are plenty of resources to learn new skills and improve them.

I'm not just some dumb kid with a whacky idea that's going to cut up this car to shove an engine in there. I've owned this car since 2016 and I'm quite attached to it, I love it. I have zero intentions of selling the car or completely ruining it. I can change course at any point. Will it cost a lot of money to do so? Yeah probably, but I've put allot of thought into this whole ordeal, if I didn't think it were possible I wouldn't be attempting it at all. At this point all I can do is execute and problem solve as I go.

The car itself looks decent but the quarter panels are rotted at the bottoms, the rocker panels are rotted, the 318 that was in it had a slew of problems, was not well maintained by the previous owner, not to mention the transmission, brake and suspension problems the car had anyways. (All of which will be addressed, the rotted panels, suspension and brakes that is). It's a '74 anyways, nobody likes the late Duster's and there are very limited restoration parts for them. The car was unsafe to drive more than just moving it out of the way. I had to neglect the car and let it sit for the past 8 years since I joined the military, got out and attended school, during which I worked at a restoration shop and got to see and work on all sorts of modified classic cars, nothing like what I'm trying to do, but some pretty gnarly drag cars.

Regardless of what everyone is saying with how terrible an idea this is, I get it, I understand. But I'm going to proceed. There are safety concerns with the whole idea, and as someone who previously worked for Cummins themselves and is consistently around high voltage, high amperage systems, safety is always a concern. When I say I'm a generator technician, I'm not saying, "oh I work on the little 5000 watt Honda generator that you take camping", no I work on units up to 2 megawatts that can push out thousands of amps, 78 liter V18's, bigger than some people's homes. So, yeah safety is always a concern.

Hot rodding is inherently dangerous, all you can do is mitigate the danger, no motorsport will ever be safe.

Lastly, this whole YouTube channel thing is a way for me to document the project, why not share it. If my channel blows up and i can monetize it, cool, I'm not doing this for likes, attention, or money. I'm doing it because I want to build a unique car, that no one else has. LS swaps are cool, but boring, chucking any Mopar into it has been done, a hellcat motor? Sure. But no one has a Coal Duster, and I mean c'mon who doesn't wanna see a Duster with a 600 HP Cummins in it rolling coal?

Added some pictures of some of the stuff I've had the privilege of working on and a picture of one of the absurdly large generators I work on

 

[Daniel Garcia]

You've said this "1,500 lb drivetrains in 3,400lb. car" thing twice now, so I'm assuming you don't understand that your math is wrong. A '74 Duster weighs ~3,400 lbs with its drivetrain. He's not adding 1,500 lbs to the car.

That 3,400 lbs is with a fully dressed small block, which means you need to be subtracting at least 600 lbs from that figure, because we're talking about a fully dressed, all iron, factory 360 right? Maybe more if it's an AC car? And then you need to subtract about 120 lbs for the transmission. So what, 720 lbs worth of drivetrain?

And as I said earlier, the dry weight on a '67 426 street hemi was ~840 lbs. So, they put those in A-bodies right? With A833's? So, now we're subtracting 960 lbs if you're comparing an A-body with an early street hemi to a 5.9 Cummins?

The op is probably gonna be adding 700 or 800 lbs to the car vs say an early 426 street hemi or all iron big block, which no one would give him any grief at all over. Yes, that's a lot, but it's not outside of the realm of strengthening the chassis.

And we haven't even addressed payload, because I'm sure somewhere there's a spec for what the maximum payload is with 4 passengers and a trunk full of junk. So even adding 800 lbs probably isn't going more than a few hundred lbs over what Ma Mopar figured that Duster could haul fully loaded with passengers. I dunno about you guys, but I've never had 4 people in my Duster at the same time, so that wouldn't even be a thing.

And it's a '74, so there's a good 100 lbs worth of shock bumpers he can get rid of.

And right, it's a '74, which no one gives a crap about anyway. At least that's what everyone says when you want to restore one right? That '74 won't be worth anything and you should get a '70-72? Definitely heard that before here.

For @Daniel Garcia, the big question I have is why the G56 transmission? Since your car is still going to be substantially lighter than a 2500 truck, and won't be towing or hauling, I bet you could use a smaller transmission than that which would definitely make your tunnel and crossmember fabrication work easier. Unless you're planning on towing 10k lbs with your Duster too...

The G56 will bolt right up to the 5.9 and I'm trying to make 600Hp at the crank, so approximately twice the output of a stock engine. The G56 will handle it with no problems, I did quite a bit of research looking for a smaller trans to use and I wanted a manual, I looked at the T56 magnum but it wouldn't hold up to the dumb amount of torque of the Cummins.

Really my best options seemed to be the ZF6 out of a Ford, the NV4500/5600, or the G56. (As far as I could tell, if you have other transmission suggestions I'm all ears, because the G56 is a behemoth of a transmission) Basically though, the G56 is lighter than the NV4500/5600 with its aluminum case and bolts right up.

If I wanted an automatic I could use any of the transmissions that came behind any of the Cummins powered trucks, but most likely a 48RE would be easiest since the 5.9 I'm using is an electronically controlled fuel system and they came with those in the trucks anyways,I could just slim down a harness from an appropriate Ram 2500 with the engine trans combo and be good to go, but that illustrious third pedal calls to me.

 

[Daniel Garcia]

OK, @Daniel Garcia, here are my thoughts:
1. Go for it. It's your car. It's your plan. And I think it will be cool.
2. I saw where a V10 Viper engine was put in a Mopar (an E Body I think). I wonder if people told him it would never work out? I KNOW that stuffing a 6 cylinder diesel in an A Body is different, but the concept is the same. You are stuffing a bigger motor in your car than it was designed for. Go for it.
3. Will it be safe? I see no reason why it can't be. I assume you have no intention of just cutting and hacking until the big motor is in there. I know that you are going to strengthen and reinforce everything as you go. A heavier car will need better brakes, but I bet you already thought of that.
Overall, I would say this. Can it be done? Yes. It is a matter of how good you are at problem solving and fabrication. As long as you plan it out, take your time, do things properly with an eye on strength and safety, you should be good. I can't wait to see the finished product. Hey, I am only one state away. When it's done, can I come and get a ride?

Specifically regarding the brakes I'm planning on using some willwoods, backed up with the hydro boost system from a Ram truck, haven't figured out which set or size yet since there's a lot to consider with all of that and at the moment I'm mostly worried about getting the engine and transmission in the car, as well as doing the necessary stiffening and strengthening (which will be done as soon as I figure out where exactly everything is going to sit).

Ideally I would like to maintain the classic muscle car look with wheels and tires, y'know big meaty tires on a smaller rim, but I'll compromise on that in order to safety stop this freight train.

As far as the ride goes, by all means!

 

[85glht]

If I lived closer, I’d come to help. I can weld and fabricate. Retired Ironworker