68 GMC to a 2003 Tahoe chassis

[75Dually]

Originally Posted by 67Monster

Working on the same thing right now. 2003 Tahoe Z71, putting 68 C10 on it. 2006 LQ4 4l80e swap doing AWD. Most of my Tahoe was already butchered up, by people parting it out. I'd have to go back and get all new wiring harnesses for the ABS and other Tahoe perks. I was curious because I think I'll be bypassing my ABS system. I also purchased a set of coil over conversion mounts from atomicfabandperformance.com. Will be eliminating all of the torsion bar mess, especially since some of it has been unbolted, cut, etc. when they pulled everything out of it.

Thanks for the info. I am staying tuned.

I would highly suggest that you do not bypass the ABS. I'm assuming that you're gonna use the stock ECU? If so you're gonna need the ABS or else it's gonna throw a ton a codes at you. Just my thoughts hope that helps.

[67Monster]

Originally Posted by 75Dually

I would highly suggest that you do not bypass the ABS. I'm assuming that you're gonna use the stock ECU? If so you're gonna need the ABS or else it's gonna throw a ton a codes at you. Just my thoughts hope that helps.

Going to have the computer tweaked to remove "non-vital" codes. About to start chopping up the shell now so I can get down to the frame and really get going. Surprised me that there are so many body mounts on the Tahoe. Never expected that many.

[75Dually]

Now that we are back from LST it is time to get back on this project. I got a lot of great ideas at the show, and plan to incorporate a lot of them.

My first order of business is to finish up the cab mounting. I came up with a better plan on how I'm going to do that now. Stay tuned for those updates.

We will also be moving some of the items in the way that either sit on the frame rails or pass over it. I want the body to sit as low as possible on the frame so it minimizes how much frame is shown below the rocker panel.

Stay tuned!

[75Dually]

LST is over, and we had a blast, but now it is time to get back on this project! I have taken the cab off so I can see what needs to be moved on the Tahoe frame. On the passenger side I have to reroute the O2 sensor wiring. On the drivers side is a lot more items. The 2 main items that need to be rerouted are the main harness, and the second is the brake lines that go back to the ABS hub. The harness is really straight forward, but the brake lines are going to take a bit of time to get them to go where I want them. Either way it has to happen.

After that task gets done I will remount the cab and take a ton of careful measurements so I can remove the center support and then fix the new mounting points. I have changed my mind on where I want to mount the cab. The center cab support runs right down the middle of the Tahoe frame, and because of this it makes the cab stay up too high for my plans. Taking out the center support lowers the cab by at least 2". Don't worry I will make a ton of new supports to replace the old OE ones, but that will be for a future post.

Stay tuned!

[75Dually]

Today I worked on rerouting the brake lines and the main harness on the drivers side. I still have to build a heat shield to protect the lines and the harness from the catalytic converter, but that will be for another day. The routing was not a clean as I would have liked it and I'm going to go back and make sure everything is neat and perfect before we button the cab portion of the build. For now nothing is touching anything, and it is out of the way so I can proceed to setting the cab back on and getting the measurements I need to make the new mounts/bracing.

One of the fun parts for me today was making the flares on the end of the lines. Each line had to be shortened and cut precisely so they would fit back perfectly in their respective ports. It is a tedious job, but I like making sure they were right the first time. Getting the cuts just right and then remembering to put the flare nut on before I made the flare (trust me if I've done it more times than I would like to admit...). You can learn a lot by watching someone do something on YouTube, but this is one task that you just have to dive in and try for yourself. If you have never made your own brake lines I highly recommend you give it a try.

My best friend has the Snapon scanner tool that you can make the ABS cycle through it's test mode. This lets the air out of the system (most of the time...). Because I pulled the lines off, the system is going to have to be really well bled to make sure there is no air in the ABS or the balance of the system.

So tomorrow I will get the O2 sensor harness on the passenger side moved inside the frame rail, which should hopefully not take to long...

Ah well stay tuned!

[75Dually]

For those of you still following this build, today I got the harness for the passenger O2 sensors moved to the inside of the frame rail and tucked out of the way. I then got the cab put back on the chassis so I could start making the measurements, but a big wind storm kicked up today which is supposed to last until tomorrow afternoon so I decided to leave it for now and pick up where I left off later in the week.

I did take some pics of the cab back on the chassis this evening. Moving the items off the frame rails and tucking them in really made a difference. I gained about and inch of drop on the cab alone from just moving those parts around. As you can see in the below pics there is only about 2" of frame rail visible below the door sills. So now I need to be careful, yes I can lower the cab another 2 inches or so, but I have to make sure that I have hood clearance to clear the LS intake. What I am going to do is assemble the front clip and install the hood and check to see just how much room I do or do not have and then adjust my plans from there.

I still need to take all the measurements of the cab on the frame and get that settled so I can have the best chance to get the fitment correct. Once I get that far it will add to the decision on the hood clearance. This is getting fun! This is the stuff I really like, solving problems...

Everyone have a great week! Stay tuned!

[Getter-Done]

Hey 75Dually
I am still following .
You are doing an Awesome Job on your build.
The wiring project you have to do takes time and patience
Great Work

[aggie91]

Getting Closer...

[75Dually]

Originally Posted by Getter-Done

Hey 75Dually
I am still following .
You are doing an Awesome Job on your build.
The wiring project you have to do takes time and patience
Great Work

Very right on the patience part! I'm actually looking forward to tackling the wiring and the other technical parts of this build. I always learn a ton, and the guys here on this forum are very helpful when you run into any issues. Thanks for keeping up with my build.

Originally Posted by aggie91

Getting Closer...

I know right!

[75Dually]

Measure, measure, measure... Tonight guess what I got figured out! You are correct the measurements on the cab placement! I have also found a couple of items that are still in the way and are going to have to be moved. One is the exhaust hanger just in front of the muffler, and the rear assembly that holds the charcoal canister on the side of the gas tank. Both are in the way of the cab and will be moved enough to clear the cab.

I pulled the cab off again so I can start to fix those areas and so I can cut the Tahoe cab mounts and move them to their new homes. I took a picture tonight of the simple wood part I'm using to move the cab on and off. The 2X4 beam I used to support the Tahoe body was perfect for my needs, so I cut it to length, and then I bolted two 2X4 side plates onto the beam. It works great. It does not scratch the inner roof because it stays firmly in place, and it makes taking the cab off with just one person a very easy chore.

Stay tuned!

[69SCSS]

Originally Posted by 75Dually

Measure, measure, measure... Tonight guess what I got figured out! You are correct the measurements on the cab placement! I have also found a couple of items that are still in the way and are going to have to be moved. One is the exhaust hanger just in front of the muffler, and the rear assembly that holds the charcoal canister on the side of the gas tank. Both are in the way of the cab and will be moved enough to clear the cab.

I pulled the cab off again so I can start to fix those areas and so I can cut the Tahoe cab mounts and move them to their new homes. I took a picture tonight of the simple wood part I'm using to move the cab on and off. The 2X4 beam I used to support the Tahoe body was perfect for my needs, so I cut it to length, and then I bolted two 2X4 side plates onto the beam. It works great. It does not scratch the inner roof because it stays firmly in place, and it makes taking the cab off with just one person a very easy chore.

Stay tuned!

That cab lift is such a great idea. I was using a piece of plywood, a blanket, and a flat plate at the end of the boom, but that looks more solid. Mind if I steal the idea?

[75Dually]

Originally Posted by 69SCSS

That cab lift is such a great idea. I was using a piece of plywood, a blanket, and a flat plate at the end of the boom, but that looks more solid. Mind if I steal the idea?

You go right ahead! Because I think the product rights to it are with the guy I stole it from!! LOL!!!

I cannot believe just how well it worked the first time out of the gate. If you have moved your cab before you know how front heavy they are and how much of a pain that makes it to move it even a little. This DIY lift just lifts it with no fuss. Could not be happier just using stuff I had around the shop. I even used some old lag bolts too... The only thing I had to buy was the 7" bolt which I got at ACE Hardware.

[cornerstone]

Originally Posted by 75Dually

Measure, measure, measure... Tonight guess what I got figured out! You are correct the measurements on the cab placement! I have also found a couple of items that are still in the way and are going to have to be moved. One is the exhaust hanger just in front of the muffler, and the rear assembly that holds the charcoal canister on the side of the gas tank. Both are in the way of the cab and will be moved enough to clear the cab.

I pulled the cab off again so I can start to fix those areas and so I can cut the Tahoe cab mounts and move them to their new homes. I took a picture tonight of the simple wood part I'm using to move the cab on and off. The 2X4 beam I used to support the Tahoe body was perfect for my needs, so I cut it to length, and then I bolted two 2X4 side plates onto the beam. It works great. It does not scratch the inner roof because it stays firmly in place, and it makes taking the cab off with just one person a very easy chore.

Stay tuned!

Looks like a nifty plan. Im gonna make one today and pull my cab back off instead of rolling it all out to the tree and using my chain hoist. Thanks for posting that pic!

[75Dually]

Originally Posted by cornerstone

Looks like a nifty plan. Im gonna make one today and pull my cab back off instead of rolling it all out to the tree and using my chain hoist. Thanks for posting that pic!

Let me know how it goes. If it goes bad I was not responsible!

[cornerstone]

It went pretty smooth... I still had some weight on the front of the cab, like dash innards, steering column, master cylinder, etc. so it was leaning pretty hard. I had my son stand on the back of the hoist just to make sure I didn't have any boo-boos. I can say that the job is done.

[75Dually]

Made some progress tonight, a small bit of progress, but progress none the less! When the cab sets on the frame it was hitting one of the exhaust mounts, and it was hitting the mount for the fuel tank carbon filter box.

The exhaust mount was the easiest because it was a simple cut and weld job. Then I threw some etch primer on the bare spots and called it good for now.

Moving on to the fuel tank carbon filter box (I hope that is what it is called?). The cab structure that spans the rear part of the cab was running into the OEM mount, so this had to go. I took the old mount off, and then built an aluminum 'T' shaped bracket. One end of the bracket as you can see is mounted to the shield, and the other side is mounted to the filter. This filter has a very sturdy mount on the cross member towards the front of the truck, and it is not very heavy so it only needed a mount to just stabilize it.

I then put the cab back on for a test fit. I could not find anything else that was an issue, so I will next work on the new cab mounts. That will be a fun job for sure!

Stay tuned!

[75Dually]

I've been working on putting a 12V Cummins in my Dually for the past couple of months, so this ride has just been patiently sitting. As soon as I can get that power plant in I will be back on this ride for sure!

Stay tuned I will be back on this before you know it!

[75Dually]

As most of you know I have been working on the 12V Cummins on my dually. This week I wanted to see what those 22" transports would look like on the 68. What it really showed me was how much real work I have ahead of myself. The cab pinch weld was 14" off the ground in these shots, and that was without tires! What am I doing here building a pre runner?!?! Now there's an idea! But seriously I need to get a plan together for the suspension changes to get this truck closer to the pavement.

Stay tuned!

[kiwikid]

on the bed cuts how many inches were removed front and back ? looks good

[75Dually]

Originally Posted by kiwikid

on the bed cuts how many inches were removed front and back ? looks good

A very good question. To make a long bed into a short bed you need to take 12" out of the front and then 8" out of the rear. You then also need to cut 8" out of the rear frame if you still have the original frame.

Now the next question is where to cut on the bed? Actually I don't know the answer to that, but on mine I did the cuts where you see them because of the body damage on the passenger side and then matched it on the drivers side. If I were to do it again without a damaged bed I would cut very close to the leading edge of the bed on the front. On the rear I would cut in the exact same spot again. The reason for this is due to the sloping body line. Your going to have to match it up or else it looks horrible. I think I found the sweet spot in the rear quarter, and only had to slightly move the slope line just a smidge when welding it up to make it line up. Also make sure your cut lines are super straight. Can't emphasize that enough. If your lines are not parallel and perfectly straight then you might have one heck of a time trying to get it to fit back together. Measure 100 times and cut once. Trust me!

Oh yeah one other point is to use a cut off wheel when you make the cuts. Run a tape line where you plan to cut and just follow the edge of the tape with the cut off wheel. Don't use a Sawzall because you will damage the panel. The push and pull of the blade really bends up the sheet metal pretty badly.

Hope that helps.

[kiwikid]

Thank you for the detailed information cheers

[75Dually]

Originally Posted by kiwikid

Thank you for the detailed information cheers

Anytime!

[75Dually]

It has been a very long time since I have updated anything on this project. I got the 75Dually finished as far as the new Cummins 12V and the new wrap on it, pic below. We took it to LST and it got 16 mpg, and ran amazing the whole way and back. Super happy with it.

So now I can get back to this build, it has been forever since I have even touched this ride, OK except to pile stuff on it!

At LST I bought a 4 link from Thorbros, and hope to be into that here soon. Then I will attack the front end and get this at least drive-able. One of the areas that I have been looking at hard is the cross members for the transmission and the torsion bars. Seeing that I will be doing away with the torsion bars I am going to more than likely going to cut that out and replace it with some tube structure that moves it further up, same for the transmission mount. Both hang too low for this project, and both can be changed without much issues.

Here's hoping that my work schedule does not go so crazy and I get some time in the shop to work on this ride.

Stay tuned!

[72 tigger]

Looking forward to it!

[75Dually]

Originally Posted by 72 tigger

Looking forward to it!

Me too! Thanks!!