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

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Daniel Garcia

Daniel Garcia

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I have some plans to make all of this work, the biggest issue at the moment is figuring out cooling and beefing up front suspension.

The engine itself is going to have to be pushed back a few inches to make clearance for the cooling pack, radiator, intercooler etc.

I'm planning on using the HDK torsion bar eliminator kit and using the QA1 shocks that are recommended and using some relatively heavy springs, at the moment some 325 lb/inch springs seem to be my best bet since they're relatively close to the spring rate of a Ram 2500.

Steering will be handled by the newer borgeson box that has a significantly smaller foot print than the box currently in the car.

Obviously I'm going to have to reinforce the "frame" of the car, planning on connecting the front and rear subframes, I'm thinking the transmission mount I'm going to have to make for the G56 I'll be using will give it some additional strength and prevent twisting.

The plan is to run an 8 3/4 rear end with the tallest gears I can find to actually utilize the limited rev range of the Cummins.

Electrical and electronics are still in the works, but I have some plans for it.

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What engine is this? Are you sure the HDK stuff is up to the task of that boat anchor of an engine?
 
67Dart273 said:
What engine is this? Are you sure the HDK stuff is up to the task of that boat anchor of an engine?
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It's a 2003 5.9L common rail Cummins, I'm not entirely sure if the HDK stuff will be up to the task, but it seems to be the best option that won't cost me an arm and a leg
 
Cummins where you really shouldn't are always cool. I've always wanted to put a 12 valve somewhere dumb but I really can't justify it to myself.
 
I'll be the one to state it.
This is a terrible idea. You're installing an engine in a car that already has a 55/45 front weight bias and literally doubling the weight of the engine.
The frame rails and structure were designed for the slant six or LA series engines that weighed 600 lbs or less and made less than 350 lb ft or torque. No current front suspension will be enough. The factory K member is far more robust than any aftermarket setup and even those are nowhere near as durable as you will need. To do this, you will need extensive structural reinforcements which may far exceed your skill level and budget.
I appreciate doing something different but in this case, Why? What possible gains do you expect that you can't get with a turbo V8 setup?
 
oldkimmer said:
Good luck 2 ya. Is there not a 4 cyl that might make life easier? Like a 4BT or something ? Kim
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There is indeed a 4bt that would be significantly easier, but I just like the idea of a 6bt, the car came with an inline 6, so why not swap in a big inline 6 ‍♂️
 
Kern Dog said:
I'll be the one to state it.
This is a terrible idea. You're installing an engine in a car that already has a 55/45 front weight bias and literally doubling the weight of the engine.
The frame rails and structure were designed for the slant six or LA series engines that weighed 600 lbs or less and made less than 350 lb ft or torque. No current front suspension will be enough. The factory K member is far more robust than any aftermarket setup and even those are nowhere near as durable as you will need. To do this, you will need extensive structural reinforcements which may far exceed your skill level and budget.
I appreciate doing something different but in this case, Why? What possible gains do you expect that you can't get with a turbo V8 setup?
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Oh, I agree this is a terrible idea, and I'm well aware that it is going to be incredibly front heavy, and it will indeed need a lot of reinforcement. I'm tired of seeing cookie cutter builds, and no one's swapped a 5.9 Cummins into a Duster....for good reason, but still.
 
Kern Dog said:
I'll be the one to state it.
This is a terrible idea. You're installing an engine in a car that already has a 55/45 front weight bias and literally doubling the weight of the engine.
The frame rails and structure were designed for the slant six or LA series engines that weighed 600 lbs or less and made less than 350 lb ft or torque. No current front suspension will be enough. The factory K member is far more robust than any aftermarket setup and even those are nowhere near as durable as you will need. To do this, you will need extensive structural reinforcements which may far exceed your skill level and budget.
I appreciate doing something different but in this case, Why? What possible gains do you expect that you can't get with a turbo V8 setup?
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The stupid is pretty much part of the point at this point. Atleast that's my outlook.
 
Daniel Garcia said:
Oh, I agree this is a terrible idea, and I'm well aware that it is going to be incredibly front heavy, and it will indeed need a lot of reinforcement. I'm tired of seeing cookie cutter builds, and no one's swapped a 5.9 Cummins into a Duster....for good reason, but still.
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You need to tell people you were reading about a 5.9 magnum swap and got confused
 
I agree with Kern Dog that this idea is ill advised. Just because something can techniclly be done does not mean it should be done. Putting a Cummins into a D150 or something would be a natural swap but shoehorning one into a smaller passenger car makes little to no sense. It's not a passenger car engine, it's a truck engine made to haul heavy loads. You're also going to have a rev limit of less than 4,000 rpm which does not sound fun.

But besides the chassis stuff, how are you going to cool it? Those things run pretty hot (215-220) and could potentially melt stuff under the hood without proper ventilation. You'll also have to science out your fuel system pretty thoroughly to run diesel. And what trans do you plan to use? Whatever it is won't fit without cutting apart all kinds of structural pieces of the chassis. So not only are you adding a bunch of weight up front but weakening whatever is behind it.

I'd think this through a little more before you start cutting stuff making the car un-sellable should you decide to abandon the project before its finished.
 
So, I agree, bad idea.

But, before we get too crazy on the weight thing- a 426 street Hemi weighs ~843 lbs dry right? And no one would question the guy if he was putting in a 426 hemi.

I’m seeing specs like 1,150 lbs for a 5.9 Cummins. So, yeah, heavier. And lots of beefing up to do. But I’m not sure it’s absolutely crazy.

Right off the bat though, 325 lb/in springs on an HDK won’t cut it. The 2500 springs are vertical. The motion ratio on those coil overs is gonna mean you’re probably gonna need to be 500+ lb/in on the springs
 
And some 2” torsion bars .
Might as well remove the windshield now vs waiting for it to jump out first time you punch it .
A 4” driveline and a minimum of a Dana 60/70 .
SS springs ( 2 passenger sides )

Reinforce the trany cross member .
 
mbaird said:
And some 2” torsion bars .
Might as well remove the windshield now vs waiting for it to jump out first time you punch it .
A 4” driveline and a minimum of a Dana 60/70 .
SS springs ( 2 passenger sides )

Reinforce the trany cross member .
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lol, 2” torsion bars. You’d have to make the rear hex anchor removable so you could install the bars.

Or you could install C-body hex anchors at both ends, that would give you up to 1.5”. That’s what the NASCAR Mopars ran…
 
I like it. I think it's cool. Go for it.
 
I was thinking a 4 cyl, massive Turbo, and 2.70 gears may be fun. but from what i understand the 4cyl is just the six with 2 cut off and it is very shaky.
 
I participated in the 2010 X-Prize 100 MPGe Fuel Economy Race (Liberty Motors #20). One of the entrants had a Mustang with a Detroit diesel that got 138 MPG and would pull 10's in the quarter. It was featured in Hot Rod Magazine around that time as well. I say Go For It!
 
DumpsterFire said:
The stupid is pretty much part of the point at this point. Atleast that's my outlook.
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That is funny. Hey, as long as you are going into this wild project with your eyes open, I do wish you good luck.
 
I just want to see how the coil overs do with all that extra weight and no torsion bars.

That said, I'm also curious why you're ditching t bars when you're running such a narrow motor.
 
in addition to all the aforementioned issues: weight, heat, cooling system, fuel, which you know going in are issues, i hope that your fabrication/chassis building skills are en pointe.

sectioning the firewall and moving/modifying the crossmember and floor means that you're compromising critical structural components of the car. this is well beyond the purview of "connecting the front and rear subframes". you should be thinking cage plus reinforcements in select areas.

handling wise, you'll never meet a corner you like.

i applaud the idea, but if i were hankerin' for the coal my choice would be a 4BT
 
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