72 K5 Duramax Swap
 

I would like to swap a 6.6 Duramax Diesel into my '72 K5. I had the original 350 motor and tranny pulled out for a 496 swap, but changed my mind and wanted to go even more crazy. I honestly have no idea where to start with this, or what I need to do. Don't know if it'd just be easier to swap body onto a duramax chassis? Or to just try to swap motor, tranny, and somehow try to get all the computer parts in there somehow...Any help would be appreciated, thanks.

Re: 72 K5 Duramax Swap
 

No offence, but if you need to ask how to do it, maybe it's best if you didn't ! Doing a swap like that takes a lot of knowledge, and you must know beforehand how you're going to approach it. If you just jump in without having a plan, you'll get discouraged and that project will end up on the back burner. My 2 cents

Re: 72 K5 Duramax Swap
 

I've seen both. Depends on how what you want for a front suspension, and even that can be changed on a Dmax chassis. They make stand alone harnesses for them.

Re: 72 K5 Duramax Swap
 

You mean something like this?

The picture is of a low mile LLY i pulled from a wrecked 2005 2500HD. The NV4500 is just there for reference so you can see the size of the motor.

But hemi43 is right, if you have to ask big man where to start, you probably shouldn't.

But since you inquired, you have two choices - either put a blazer body on the duramax frame or put the duramax in the blazer frame.

The first one seems to be the most popular swap as the frame already has the d-max motor set in it. Just need to shorten the frame to 104", set the body on, make cab mounts and figure out how to mount the clip with radiator, coolers and intercooler. Personally, I dont like to see the frame hanging down under the rockers as the frame of the d-max is tall. So guys will add big rock sliders or steps to try and cover it up. But you can still see it. And lets face it, while the stock IFS blows you do have the massive AAM 11.5" rear axle.

The second one is way cooler and more difficult - put the d-max in the blazer frame; this will require more work. You have to start with finding upgraded one ton axles. 35 spline dana 60s and 14 bolt at the minimum b/c I wouldn't run 900+ pound motor, 200+ pound allison with 360HP/660TQ on a D44/12 bolt. A tune and exhaust will take a stock duramax to 600HP/900TQ. A bi 14 bolt with 10.5" ring gear is small compared to the 11.5" AAM axle in the duramax. Then you will have to fully box the frame complete from end to end with new cross members and figure out a cool way to set the motor in there so you can shut the hood.

What are you going to do about trans? The Allison would be the way to go but I have seen both 4L80s and NV4500's used in swaps but those are on detuned motors. And what about a transfer case. You can go with the stock Duramax TC but that is driver side drop so you will need to find a Ford Dana 60. Or you can find a passenger drop NP205 to mate to a chevy trans and keep the passenger side drop axle. The Allison will take a decent amount of sheet metal work on the trans tunnel to get it fit as it is dramatically bigger than a stock trans.

A few people make standalone harnesses - PPE in Fullerton, CA does a nice job. There are others that can make the harness and load a few tunes - you will need a way to disable the VATS, emission and all the other BS that will keep your truck in limp mode. You can run stock gauges with the standalone harness.

Figure new suspension as the extra weight will require upgraded leaf springs or coilovers. If you go coilovers then you have to go 3 or 4 link. With a shortened frame you are going to have wheel hop, so figured a rear traction bars.

You will need to figure out fuel system, cooling and plumbing. That is where the real time and money will happen as I am not sure a stock intercooler, radiator, trans cooler, condenser will fit in the blazer.

Lastly, don't forget about 4 wheel disc brakes.

Few questions, you ever measured a duramax out of the truck? Height, width and length and compared to a gen 1 blazer? While it is comp to a BBC just with a lot more girth. I bought my LBZ new in 06 and have driven daily ever since. I like to think I am pretty familiar with them.

The duramax swap feels like the offspring of a LS and 6.5 diesel mated together.

Did I miss anything?

JR

Re: 72 K5 Duramax Swap
 

4bt or even 12v cummins would be way easier

Re: 72 K5 Duramax Swap
 

Everyone thinks because they are mechanical with little wiring they are WAY easier. I hate to tell you, if you do a swap correctly, it takes a good amount of time. If you sent the wiring out to have done on the Duramax, I don't see it being that much of a bigger job IMO. Do what you want. Asking questions is how we all learn. I for one am not big on body swaps so I'd probably transfer everything over to the K5. I just don't like how the newer frames hang way down under the body. Again just my opinion. Look at 72duraburb's thread and you can see how one looks in a 72 burb. He has done a few and is currently doing his GMC but is a 2wd drag type build.

Re: 72 K5 Duramax Swap
 

I just searched 72duraburb's build thread. So impressive - running the stock frame with twins.

And I couldnt agree more - the frame on the new trucks hangs so low it kills it for me w/ the body swap.

Shot him a PM as I am curious to know his motor mount set up. And he is running e-fans. Probably has to be done when trying to jenga a radiator, condenser, intercooler and trans cooler in the front.

Then keeping the stock A/C and running twins is blowing my mind. 800 HP with A/C...amazing.

John

Re: 72 K5 Duramax Swap
 

Duramaxs are awesome.

My previous 03 made 730ftlbs of torque after a efi love tune.

My 08 will burn the tires off into 3rd

Re: 72 K5 Duramax Swap
 

We are just about to get started on one that will set the precedence for all K5 Duramax swaps in the future. We will start posting next week.

Re: 72 K5 Duramax Swap
 

Don't take the negative replies personally. It's just a VERY complicated swap. Folks who think they know what they're doing on a swap like that, probably don't... lol. If you can find the right help and have the $$$ to throw at it and REALLY want it, go for it. The sanity check responses are just that. Anyone would be crazy to do that swap. But crazy swaps are sometimes the best, because almost everything that can be done to a Blazer, has been done... That said, an LS/paddleshift automatic would probably be a lot easier to design and enjoy and your resale market would be a lot bigger someday... :)

Re: 72 K5 Duramax Swap
 

You said it yourself. That's my fantasy truck. Shorten the Duramax to Blazer wheelbase and transplant the body...

Re: 72 K5 Duramax Swap
 

https://youtu.be/1NIv6fePLqI

That's what they did if you read the comments. Shortened the frame and made mount. That thing is clean.

Re: 72 K5 Duramax Swap
 

so..did you ever do the swap?

Re: 72 K5 Duramax Swap
 

orrrrrr! how to make a small fortune on a resto mod, start with a large one