68 GMC to a 2003 Tahoe chassis

[75Dually]

Today was a layed back day. I did get the cab all squared on the frame and then started to mark and drill the location for the rear cab mounts. No pictures just yet, I mean they are just holes in the floor... The interesting part is going to be the new rear frame mounts that will meet up with the existing Tahoe body mounts. I think I have found a decent way to make the rear cab mounts. I hope to have some pics in the next couple of days.

Merry Christmas everyone! Be safe and let's make 2018 one of the best years ever!!

[Dieselwrencher]

Nice work on it! 58 or so days means you're going to be busting your hump on it!

[75Dually]

Originally Posted by Dieselwrencher

Nice work on it! 58 or so days means you're going to be busting your hump on it!

Yeah tell me about it! I told myself that all it has to do is roll up on the trailer so it can go to LST. I still have to finish the mounts for the cab, bed, the core support, front and rear bumpers, etc... Oh yeah and hopefully I can get to some of the suspension mods. I actually like having a deadline because it helps motivate me to get out there, concentrate, and get done what needs to get done. I use to do this for all the years we did the Power Tour. Man we built some fun stuff that went the distance. Spent a lot of sleepless nights right before we left too.

Git-r-done!

[75Dually]

I started on the rear body mounts this evening. This is the main portion that will be welded to the truck floor pan. It will have a couple of additional supports added before it is all said and done. All the up's and downs you see in this part match the profile of the floor pan. The tubing you see here is 2 1/2" with 1/8" wall.

Lots of getting up and down, card board, tape, and tons of measurements!

I should have a couple more pics once it gets final mounted and welded in.

This will all make sense once you see it in place and welded in.

Stay tuned!

[75Dually]

Today was a good day in the shop. I've been working on the rear end on the dually, now I have to change out the bearings, but at least the ring and pinion are in super shape.

On to the 68! I needed to drop the front core support and that meant that I had to cut the front sub frame. So I got all the little bits out of the way and cut at an angle the front sub frame. That way I could lower it however much I needed. I did cut the front Tahoe bumper mounts off so I can make way for the front frame horns off the 68 frame. That way I can mount the bumper without any hassle. I do have to wait to weld it back up until I get the cab mounting all finalized.

I did not take a picture of it but I cut the 2 Tahoe body mounts off that were on the front sub frame. I need to move them back about 4 inches and use them for the core support mounts. Again I have to wait until the cab is finalized before I can weld these mounts back up, but that should not be to long from now.

Stay tuned!

[79azc10]

This is going to be nice

[aggie91]

Nice job Chris. I thought I was already following along, but I guess I was not.

I'm all set up for LST, and plan on brining you an item that's in my shop!

[75Dually]

Originally Posted by 79azc10

This is going to be nice

I certainly hope so! Thanks for following along!

Originally Posted by aggie91

Nice job Chris. I thought I was already following along, but I guess I was not.

I'm all set up for LST, and plan on brining you an item that's in my shop!

It is going to be like a second Christmas! I'm looking forward to next month!! Thanks again for storing and picking that up for me again... I still owe you dinner!

[75Dually]

Tonight was about starting to clean up the firewall. I really need to remove the cab again on the 68, but the dually is in the way, and that won't be moving until I repair the diff. I got a lot of the lose wires, the choke cable, the old speedo cable, and a lot of odds and ends removed. I also got the heater assembly taken out too. I took an old circular wire brush in a drill and got a lot of the material removed. I was then going to use a flapper disc to remove the rest of the sealant that was left on the firewall (pic below), but I had enough dust tonight from all that and decided to call it a night.

One thing that I would like those guys reading this who have never done a project of this size to understand is that there are a million nasty jobs that those 30 minute shows never tell you about. The gunk that just won't come off the firewall with anything but an old wood chisel (true story, had to use an old wood chisel tonight to remove that old hard sealant between the blower box and the firewall. That stuff was flexible 25 years ago, and now was as hard as a rock!). I don't want to scare anyone off, but just make sure you don't lose heart when you have to get all those not so fun jobs done. I've seen a lot of guys, even pros, drop a project because it stopped being fun about forever ago. Keep that final vision in your mind, go get a rendering done of the final result, or bring over your buddy's to help keep you motivated. The first time you get to fire it up and go around the block is an over the moon feeling that you will never forget. Ok that is unless it pukes on the way home, but that is a different story....

Stay tuned!

[75Dually]

Just a short side note, tonight while I was working on the truck I wanted to take out the old door seals. Oh boy! At some time in it's history someone had glued the weather strips with what should only be described aggravation glue!! Every inch of these crusty, nasty, old dirty strips had this mega glue. What should have taken 10 minutes max, went on for over an hour. I mean really... Dude!

They are now off and ready to be cleaned up and the new seals installed in the near future. Man is nothing ever easy... This is my hobby, but man there are days!!

Stay tuned!

[Dieselwrencher]

I've had a few of those seals too. It sure is a PITA!

[75Dually]

Originally Posted by Dieselwrencher

I've had a few of those seals too. It sure is a PITA!

Word!

[Advanced Design]

Another cool build! I never realized a Tahoe chassis could work...tagging along for the rest.

[75Dually]

Originally Posted by Advanced Design

Another cool build! I never realized a Tahoe chassis could work...tagging along for the rest.

I've seen these done with the 4WD Tahoe chassis, some of them are really cool, but I have yet to see one finished that is 2WD. So lot's to learn, and lots of problems to solve. At least my wife knows where I hang out! The shop!!

[67Monster]

You keeping the ABS system or bypassing?

[75Dually]

Originally Posted by 67Monster

You keeping the ABS system or bypassing?

Keeping the ABS if at all possible.

[67Monster]

What major problems have you had to overcome so far? or can see will be a problem before you're finished?

[75Dually]

Originally Posted by 67Monster

What major problems have you had to overcome so far? or can see will be a problem before you're finished?

My 1st problem to overcome is the cab to frame mounting. What I want is the cab as low as possible on the frame without interfering with the components on the frame. For now that's my major hurdle. I'm sure there will be lots more but that's why I did this project was to find the hurdles and overcome them. I hope you like this project I know I do!

Stay tuned!

[67Monster]

Originally Posted by 75Dually

I hope you like this project I know I do!

Stay tuned!

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.

[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!