Wrecked LBZ Frame Swap

Tommy's Auto

New member
Oct 9, 2024
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Springville, UT
I'm new to the forum, but not new to the Duramax world.
I own a shop "Tommy's Auto in Springville, UT". We buy salvage Duramax trucks and rebuild them, been doing the rebuild thing for 39 years. We also have approximately 60 Duramax trucks from LB7 to L5P that we part out.
The reason I joined the forum is because I'm toying with the idea of building me a 2006 Silverado 2500 crew cab short bed, but I'm going use a complete rolling frame from a 2015 because of how much stronger they are, the heavier suspension, and bigger brakes. I was going to go with a built LBZ, but now thinking L5P and maybe the 10-speed.
YEAH, I KNOW, here comes all the comments about why go to that much trouble? Or, it's not worth the time and effort. Well that's for me to decide what to do with my time and money. Sorry for the rant, but you all know it's coming.
I know a few people have done similar swaps and I would be SOOO grateful for any information on do's and don'ts about a swap like this.
The pictures are of the last 2006 GMC LBZ that I built a couple of years ago, it had only 66K miles on it.
 

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2004LB7

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Dec 15, 2010
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Norcal
Yeah, as Tom said.

Only time we usually tell someone their crazy or not worth it is if they don't have the knowledge, money or time to do it, or do it right. We are pretty realistic here with what can be done. But you are also going to be taking to a bunch of die hard modders and performance freaks so this something we would probably all want to do if we had your parts and resources. So I say build away and keep us updated on progress

I vote for classic GMC body like from an 03 LB7 to LBZ, Engine and transmission from L5P, LB7 emissions, and whatever frame you can fit under it from LML or L5P. If you can fit an L5P frame then that would simplify the engine and transmission mounting.
 
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Nate’s Dmax

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Dec 11, 2020
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That would be an interesting build. I’ve been toying with the idea for some time now. What I haven’t been sure of is how to make the classic ABS work with the bigger brake system of the LML and up trucks. On other problematic point for me is how to mount the LBZ in a LML frame as the LBZ mounts are offset and LML are straight across. You wouldn’t need to go with 2015 frame to get the heavier frame as that started in 2011.
 

Tommy's Auto

New member
Oct 9, 2024
8
8
3
Springville, UT
That would be an interesting build. I’ve been toying with the idea for some time now. What I haven’t been sure of is how to make the classic ABS work with the bigger brake system of the LML and up trucks. On other problematic point for me is how to mount the LBZ in a LML frame as the LBZ mounts are offset and LML are straight across. You wouldn’t need to go with 2015 frame to get the heavier frame as that started in 2011.
I already have a couple of 2015 LML frames from trucks that we dismantled. I thought I was somewhere that someone had motor mounts to fit the L5P into the LML frame. I gotta do a little more looking. As for the ABS stuff, if I can't figure it out, I'll just disable the ABS system. I can drive without ABS.
 

Tommy's Auto

New member
Oct 9, 2024
8
8
3
Springville, UT
I put the 2006 bed on the 2015 frame the other day and 6 of the 8 holes lined up. It won't take much to get the other 2 lined up. I can't wait to put the cab and front end on and see how the rest of it mounts and lines up. If I do go through with the L5P, this is the one that I'll use. It's a 2023 and has only 14K miles.
 

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Nate’s Dmax

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Dec 11, 2020
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For motor mounting Werli Fab could surely put something together for you. All it would need to be is a L5P engine side with a LML frame side in there custom mount line. The bed bolts that dont line up are the next forward from rear ones right? If you do get the L5P running in the classic body make sure you document the process so you can help others do the same thing. There may already be someone out there that has done it if you can find them.
 

Tommy's Auto

New member
Oct 9, 2024
8
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Springville, UT
UPDATE:
As much as I'd like the L5P, I think I'm going to keep it a little more simple as far as the drive train and electrical system goes. When you're out on the road, you want to be able to fix it without getting SpaceX involved. I'm going to go with the LBZ and the 6-speed and keep everything on the top side that goes with it.
The whole body bolted right on for the most part, I will have to make a couple of small changes (very happy about that). The engine mount pedestals on the frame will need to be moved forward about 3", and I'm not sure on the elevation yet. I can either modify the pedestal to accept the LBZ mount or use and alter a pair of LML engine mounts to fit the LBZ block (I think the second one is easier). The radiator support mounts on the frame will need to be changed to the classic HD ones because they are 2" taller. The radiator support on the newer trucks is 4" taller than the classics, that's why they used the shorter mounts on the frame. I'm considering altering the LBZ radiator support and using LML radiator and intercooler because they are 4" taller.
I don't mind making the few changes for the drive train to fit. The wheelbases are 2006 153" and 2015 153.7", so about 3/4" longer, and I was wondering where that might be and it looks like the extra length is between the front wheels and the body (which is awesome), less chance of rubbing tires.
 

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Nate’s Dmax

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Dec 11, 2020
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Hey good work. What i have in mind when i do this is using an LML block and rotating assembly so i dont need to move the frame to motor mount. Also if you would get yourself a set of LML motor mounts the holes would line up for you. Block side is same bolt pattern from LBZ to LML.
 

Tommy's Auto

New member
Oct 9, 2024
8
8
3
Springville, UT
Hey good work. What i have in mind when i do this is using an LML block and rotating assembly so i dont need to move the frame to motor mount. Also if you would get yourself a set of LML motor mounts the holes would line up for you. Block side is same bolt pattern from LBZ to LML.
I was thinking the same thing with the LML block and mounts. From what I understand, you need to run the LML timing cover and some other stuff on the front of the LML block. The mounts for LML are a little different than the LBZ where they bolt to the block, one of the holes is in a different spot. But easy to change the hole.
 

Nate’s Dmax

Active member
Dec 11, 2020
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I was thinking the same thing with the LML block and mounts. From what I understand, you need to run the LML timing cover and some other stuff on the front of the LML block. The mounts for LML are a little different than the LBZ where they bolt to the block, one of the holes is in a different spot. But easy to change the hole.
Yeah you are correct for the front cover. I disagree on the mounts tho because i use the same attachments on my engine stand for all of them up to the L5P which is different.
 

Tommy's Auto

New member
Oct 9, 2024
8
8
3
Springville, UT
I was thinking the same thing with the LML block and mounts. From what I understand, you need to run the LML timing cover and some other stuff on the front of the LML block. The mounts for LML are a little different than the LBZ where they bolt to the block, one of the holes is in a different spot. But easy to change the hole.
Left is LML...Right is LBZ
 

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