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Which Duramax would be ideal for a swap and what does it really take to make it run?

53K views 12 replies 11 participants last post by  New to me GMC  
#1 ·
Considering putting a Duramax in my 63 Chevy SWB C10 Fleetside based simply on the fact that I've been running around in a friend's 2010 GMC 2500HD with a Duramax and love the way the power and torque thrust on and on and want to do something different for my C10 than just another SBC.

Physically getting the Duramax and associated transmission in my C10 will not be an issue.

The catch is that I have limited understanding of the differences in Duramax models and also want to know what else is need to make the Duramax run besides diesel. What all is needed concerning electronics and the like for this type of conversion?

Looking forward to your thoughts.
 
#2 ·
Best bet would be finding a totaled truck and using it as a donor, maybe a regular cab long bed and fitting the 63 on top of that frame, with some cutting and metal work to fit the body. Would be easier, Then the power train, is in a solid home. Just my thoughts! and my vote goes for lb7!
 
#3 · (Edited)
I was looking for an LBZ for my 1/2 ton but settled on a LLY due to the higher price that the totaled LBZ trucks were selling for. Picked up a decent condition wrecked 2005 CCSB for $5700 OTD.

Electronically I was lucky to have a relatevely easy job, I put EVERYTHING from the 05 into the 99 cab and frame, so there were no conversion issues. You would for sure need to keep the OEM ECM and TCM, might be able to run aftermarket gauges with their own senders. Depending on what you're after for the truck, you could try to integrate the rest of the interior electronics as well (cluster, radio, locks, HVAC, window motors, etc...)
 
#4 ·
Post a picture of the '63. I love these old trucks.
 
#5 ·
LBZ for sure
 
#6 ·
hey peanutbutterroad, I am wondering the same thing you are. I am needing the same answers for my project, a 56' chevy short (23') bus. I am hoping the guys that have answered (coincidentally all different) your question, might be able to elaborate on why they would recommend their pick for the best model choice.

I have been told by a friend that LB7 is a good choice for simplicity, other than the injectors. Can anyone testify to another model being equally as simple (electronically and tune-ability) as the LB7.

As far as power, it doesn't need to be a powerhouse (anymore than they already are). Minor upgrades would be fine, so if you are answering this with the only argument that your choice is only for the most power, I guess I'll need more haha.

I'm new to the forum so I hope I did this right.

Thanks guys!
 
#7 ·
LB7's have injector issues.
LLY's tend to pop stock head gaskets but once swapped with a newer style gasket seem to be fine.
LBZ will be popular because they dont have many issues,make the most power from the factory out of these three and they are the last model before the DPF.
 
#9 ·
I 2nd that first comment, dropping your 63 cab/box on a donor trucks frame. That way you not only get the motor and tranny. But also all wiring, computer, axle, and a MUCH stronger frame to handle the power.
As for which truck to get as a donor JDT4430 mentioned the major pros/cons of the first 3 generations. Then the next 2 (LMM & LML) have emissions equipment (which can be deleted) but are still essentially the same engine, just with higher compression, injection pressures etc...
LB7 2001-2004
LLY 2004.5-2006
LBZ 2006.5-2007
LMM 2007.5-2010
LML 2011-Present

Also we want to see pics of that 56 short bus too!
 
#11 ·
Peanutbutterroad:

I've looked into this swap extensively for a 73-87 C10 SWB and have done a good bit of research. Others have covered the LB7 vs LLY vs LBZ swap, but I would highly recommend the LBZ for its power potential and lack of emmissions. The LMM and LML can be deleted, but with the higher price for newer donor trucks and added cost to delete them, I wouldn't consider the latter unless the donor truck was already deleted and the price was right. Another thing to consider is EFI and others are moving towards not supporting deletes.

The next consideration is what transmission you'll run. If your getting a complete donor, most likely you'll run the allison. Another reason to go LBZ because you'll get the 6spd Allison. It has a .62 OD ratio that will make a 2wd street truck like yours run 80mph on the interstate at somewhere around 1800rpm depending on the rearend ratio. This translates to mpg's in the mid to high 20's in a 5500lb truck. The 5 speed alli will probably run closer to 2300 at 80 all things the same. If you find a Express or Savanah cargo van/ambulance/cutaway van with a duramax you'll get a 4L80 and a detuned duramax. The 4L80 can be built to handle a mild dmax in a light vehicle, but it won't hold a candle to a allison. A stock LBZ and stock allison should handle 550hp on nothing but a tune and supporting mods in a light truck. The next choice would be the zf6 6 speed manual. It would make the swap a little easier, all you would need is a dual disc clutch to handle anything a built dmax could dish out. They're just really hard to find. I've tried to find pics of a zf6 next to an allison, but can t find any. I think the zf6 will have a lower profile for fitting under the trans tunnel. The allison is massive, so plan on modifying your trans tunnel. dmax trucks come with a factory 2" taller frame to compensate for this. This is also why the vans don't come with a allison.

To make a dmax run in a swap like this, you'll need the ECM and harness from the donor, the TCM if it's an allison, (vans w/ 4l80 wont have a seperate TCM, nor will zf6's obviously) You'll also need the acc pedal because its drive by wire. There may also be a acc pedal control module that you'll need, but I'm not positive. If you can get your hands on a wiring manual, there is a LOT of unneeded wiring that can be removed from the stock harness to clean it up. There are also LSX shops that can modify the harness for you. PPE will do this too. All you really need are the engine/trans sensor harnesses, starter circuit, glow plug module and circuit, obd port, etc. Wipers, Headlights, etc. will still be controlled by the 63's harness and switches. For the 6 speed alli, I would try to get the +/- shifter button and wiring harness out of the shifter and mount it somewhere in the truck, same with the tow/haul button. You should be able to make the stock column shifter or an aftermarket B&M/Lokar/Hurst shifter work with a cable linkage to the transmission. The 6 speed has PRNDM, so you may have some extra gates you won't use. The 5 speed alli has PRND321 so it would work with an aftermarket shifter. If your factory column only has PRND21 you may have to modify it to work but it should be doable. Another option is to use the donor trucks steering column, wheel and shifter but it looks ugly in an old truck unless you swap the entire dash, seats, and interior which has been done on a few swaps.

You can integrate the 63's gauges by tapping into the oil pressure sensor with a tee fitting, coolant sensor with a tee or another coolant plug in the head, volt gauge is obvious, and the fuel sender will be the stock 63 if you keep it's tank. A better option may be a fuel cell, which can be ordered with a sender that matches the output of the factory sender. The dmax ecm/tcm will need an electronic speed signal from it's own speed sensor on the transmission. Tach will be the same. Getting a mechanical speed output will be tricky, the easiest thing I can think of is running a divorced transfer case just to get a mechanical speedo output. Going with aftermarket electronic gauges will be easier. You should be able to tap into the dmax's speed sensor to get an aftermarket speedo to work. I've also seen people add a toner ring and hall effect sensor to the crank balancer to get a aftermarket tach working. An easier option would be a tuner like the hs race tuner or bully dog gt that will cover all of your gauges. Some people even graft the donor trucks gauge cluster into the swap vehicle. On my swap, I plan to graft all matching autometer gauges into the c10's cluster and use the Autometer sending units (5" tach and speedo, 2 5/16" oil, water, volts, fuel level) and run Autometer 2 5/16" boost, pyro, etc. in a gauge pod somewhere else.

On the fuel side, I would recommend a Airdog or Fass filter and water/air seperator mounted on the frame. It will keep the CP3 from starving and filter the fuel better than the stock filter. I'm not too familiar with 63's but I'm thinking the stock tank is behind the seat like the 67-72's. If so I would highly recommend a fuel cell where the spare tire goes. If you go this route, you can run braided fuel lines from a sump on the bottom of the cell to the Airdog, and braided lines to the engine. If you run an airdog or fass you won't need the stock filter and filter housing on the engine. PPE makes a filter delete kit I believe. You can run the fuel lines straight to the delete kit on the engine, and you'll need a return line straight back to the tank.

On the air side, you should be able to graft a stock dmax or cummins intercooler into the 63's core support. Same with radiator. Use a radiator out of a dmax truck and make it fit. Or get a direct replacement 4 core aluminum radiator and custom intercooler for the 63. You can run hi flow dual electric fans on a thermostat if the dmax's clutch fan wont fit, but it would be better. The turbo(s) are all up to you. You may have to run custom fabbed intercooler pipes.

On the rearend, I would run at a minimum a 14bolt 9.5" semi floater. You can get 5 lug axles for it, but 6 lug's are easier to find. A ford 9" could work, they can be built pretty stout. I've also seen 6 lug conversion kits for 10.5" 14bolt full floaters, but I don't know how the wheel spacing would be. I doubt the 12 bolt in your truck will last long but you could always build it with a spool and chromoly shafts. I would also run a high gear, 3.42 on the low side, but I would run a 2.90-3.08. The higher the gear, the more it will load the engine and keep the turbo spooled in a light truck.

Now, the real downside to our swaps: the factory frame on C10s is extremely weak and will twist bad under the torque of a dmax. At a minimum I would plate the inside of the frame wherever possible. Cross braces would help. I would even look at using a frame from a 88-98 rcsb or 99-06 rcsb. The wheel bases are pretty close to swb C10s and would be a LOT stronger. In my swap, I am looking at using a 07+ 4x4 tahoe frame to have coil-over 4x4 IFS and a 4link coil over rear to build an awd dmax powered street truck. The wb is only 1" shorter than a C10. If you have leafs, I would highly recommend traction bars or ladder bars. If you have the trailing arm ( I thinks that what its called) I would beef them up too. I would get some c30 springs for the front or order a custom spring or even air ride.

For brakes, you'll need to swap the vac assist or manual brake master cylinder for a hydroboost unit out of a c30 or even the dmax donor. The dmax doesn't have any provisions for vacuum. (if your truck has any vac operated accessories you may need to run a vac pump off of a custom bracket and pulley setup, and if you do so can run the stock vac assist master cylinder) A stock, tuned dmax in a 5500lb truck will probably run low 12's if it can hook, so I would highly recommend aftermarket brake upgrades like willwood or baer. You could probably run c30 spindles and brakes if you don't mind having 8lug wheels on a C10, which would make the rearend choices much easier and cheaper. You could run C30 parts on the front and use the donor truck's disc equipped AAM 11.5" axle in the rear. That, combined with the late model hydraboost unit and EBC yellow stuff brake pads would be a cheap, but very effective brake setup.

As some have said, you may be better off to find a reg cab long bed donor and shorten the frame to resolve the weak frame issue and drivetrain/break issue. You can find 8lug wheels that will look good on a lowered c10 street truck. Engine and trans mounts won't be an issue either. Just keep in mind that the dmax frame is really tall and heavy.

I'm sure I'm missing some things, but this should get you started. Do a search for 69 C10 Duramax. He's running in the 9's and has a nice setup. He has a thread out there somewhere that talks about the build, but it's not a full build thread.

Good luck and keep us posted.
 
#12 · (Edited)
I too have been do I tons research on a D-Max swap. Im searching for a 2010 Van. They had the LMM sttke engine along with a 6L90E trans.

From the research I've done the 6L90E is the modern day 6spd version of the 4L80. They put this trans in the ZL1 Camaro and the CTS-V. PAC Transmission even sells a reasonable rebuild kit to hold over 1200hp and comes with a new quad (4) disk converter.

Im planning on a 88-89 GMC single cab short bed 2wd Sierra. I dont have plans for 1000+HP or anything. Just a nice 500hp or a little less daily driver.

If I was going for big power I'd keep with plans on stuffing a allison in there. But for what I plan on I believe a mild build 6L90E will do for me plus I still have 6spd.

No separate controller for the trans or anything. I plan on using the van steering column, cluster, and related accessories. I'd still retain the manual option in drive mode, and a tow haul mode.



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#13 ·
IMHO, Vans are a great choice for hot road donors. If I was going do to a build like the OP wants I too would be looking for a van or cube truck. Lighter weight trans, and usually cheaper to buy.


Don't think HG failure is not a potential issue with an LBZ. The early LBZs got the original design gasket.