1970 C-10 / 1998 Yukon hybrid
 

Hey guys, I'm new to the forum. I've been searching C-10 stuff for weeks and I kept landing on this forum. I thought I'd share some pics from my C-10 project I just started. My plan is to put a rat rod style C-10 body on a 4X4 Yukon frame retaining all the factory options except the air bags. I'm thinking I'll go with 20" wheels but I'm waiting on that until I get the body situated on the frame so I can get the offset correct. I'm planning on using the floorpan and firewall from the Yukon since the mounts will bolt right onto the frame. Also the steering column and HVAC components will bolt right in, I hope...

Re: 1970 C-10 / 1998 Yukon hybrid
 

I suppose most will cringe at what is basically a re-bodied Yukon, but I kinda dig it. Dang sure will be more fun than driving that Yukon.


What is the distance from the firewall of the Yukon to the front axle centerline? Any difference from the C10? Just curious if that is gonna put the back of the drivers seat out past the back wall of the cab in order to keep the front wheel centered in the wheelwell? Those Yukons had so much more leg room.

From one guy not afraid of a sazall to another, carry on.:smoke:

Re: 1970 C-10 / 1998 Yukon hybrid
 

Please keep us updated. I saw a similar project several years ago, where a guy took a newer truck and kept the newer firewall and dash and mated a 67-72 body to it. It looked pretty nice. I've searched, but I can't find it anywhere.

Good luck on your build. It should be very interesting.

Re: 1970 C-10 / 1998 Yukon hybrid
 

This is very similar to what I am wanting to do, just with a 2000+ Tahoe or Yukon. Keep us updated on progress!

Re: 1970 C-10 / 1998 Yukon hybrid
 

Thanks for the input guys. I started fitting the floor/firewall last night and the firewall is forward about 4 inches. This may not be a bad thing though because I was worried that my steering column was gonna be too long. I plan on test fitting the column tonight to see if I should try to move the firewall back or just fill in the gap with sheet metal. The airbox intake is gonna be tricky as the stock air intake setup is completely different. I may try to incorporate more of the Yukon air box/ intake components. Cooper, I think my seat is gonna be fine. The front outer bolt holes even line up for the stock bench seat! I'll attach a pic of the pan. As for cringeworthy crossovers, here's my last project.

Re: 1970 C-10 / 1998 Yukon hybrid
 

So if I'm reading this correctly if you fill the gap from the firewall you will have an extra 4" of leg room? If so, that is perfect. Our trucks aren't the roomiest vehicles and 4" more would be amazing.

Re: 1970 C-10 / 1998 Yukon hybrid
 

Sorry about the million questions but is the pic with the cab on the frame at the ride height you're going for (I hope so, it looks great) and have you lowered the suspension at all? One last question, what size tires are you running?

Re: 1970 C-10 / 1998 Yukon hybrid
 

Actually the current ride height is not unobtainable. I set the frame down on the bump stops just to get a starting point. I figure it'll end up 2 or 3 inches higher. I plan on running 20" wheels so that should help keep the same stance. It has the stock 17" wheels on it now with some tires I grabbed out of a local tire shop's junk pile just to roll around the shop on. 230\50-17 on the front I think and I can't remember on the back. As for the legroom, yeah, easier said than done but my plan is to extend the cowl out the extra distance to meet the late model firewall and hopefully that'll mean more legroom and room for the heat/air unit under the dash.

Re: 1970 C-10 / 1998 Yukon hybrid
 

How close is a standard shortbed to fitting right on? I know that the tahoe you used is the same chassis as a regular cab shortbed of the same vintage

Re: 1970 C-10 / 1998 Yukon hybrid
 

I didn't realize that the chassis was the same as that year SWB, thanks for the info. If the numbers I found are correct the wheelbase is 2.5 inches longer than the C-10 SWB. My body is a LWB so I was already planning to shorten my bed anyway. I figure a few extra inches of bed won't hurt anything and may even look better. I'm also planning to incorporate the Yukon gas door setup into bedside behind the left rear wheel.

Re: 1970 C-10 / 1998 Yukon hybrid
 

Cool build, Here is a similar project that has not been finished. Might get some ideas from this guy.

http://67-72chevytrucks.com/vboard/s...d.php?t=498570

He went from a 2wd to a 4wd but it looks like yours is quite low, you did say in the first post that it is a 4x4 Tahoe so is this staying 4x? kind of confused me there.

I have to ask the dumb question on the Porsche.. How does the trans drive the rear wheels if the drivetrain is in backwards? Or is it front wheel drive?

You clearly have some fine skill so I am sure this will be a clean conversion. Keep up the good work. :metal:

Re: 1970 C-10 / 1998 Yukon hybrid
 

Thanks! The Porsche is a AWD car from the factory. It has all the stock drivetrain with a adapter plate to bolt the engine to the transaxle. Imagine a VW bug transaxle with a torque tube coming out of the front going to a front final drive unit. Here's a link to my build on it.
https://www.google.com/url?sa=t&rct=...Ompe5CeHRwGhJQ

Re: 1970 C-10 / 1998 Yukon hybrid
 

67c10, My truck will retain the 4X4. It has the push button setup and I'll be using the Yukon harness and all the electrics right down to the auto light sensing rear view mirror with the built in compass. 4X4 will not be for offroading obviously, more for towing and maybe icy conditions and the like.

Re: 1970 C-10 / 1998 Yukon hybrid
 

Ok I read the 993 tt thread that is some nice custom work. I will be anxiously waiting for some action on this one. :metal:

Re: 1970 C-10 / 1998 Yukon hybrid
 

I got the cab situated on the floorpan and spot welded in place. I got the bracket the brake pedal and steering column mount to fitted last night. Looks like I will have room for the Yukon gauge cluster in the dash too. Here's a couple of pics of that and of where the firewall sits in relation to the stock C-10 firewall.

Re: 1970 C-10 / 1998 Yukon hybrid
 

Nice, that won't be that bad to fill the gap.

Re: 1970 C-10 / 1998 Yukon hybrid
 

Does anyone know the thread size and pitch on the fender bolts that go into the cowl? I'm guessing 5/16X20? I'm not that good with standard bolts and I have almost none in my shop to try.

Re: 1970 C-10 / 1998 Yukon hybrid
 

ok, i'm subscribed for sure. if it's anything like that 996, this is going to be one of those "i can't stop talking about it" builds.

Re: 1970 C-10 / 1998 Yukon hybrid
 

Thanks Mark! I'm really excited about the truck. I had a 70' when I was in high school in 1989 and it's bringing back some good memories.

Re: 1970 C-10 / 1998 Yukon hybrid
 

This is going to be another fun one to watch ,In in .

Re: 1970 C-10 / 1998 Yukon hybrid
 

Very cool project, subscribed!

Re: 1970 C-10 / 1998 Yukon hybrid
 

Wow! I'm in

Re: 1970 C-10 / 1998 Yukon hybrid
 

should be 5/16"-18

Re: 1970 C-10 / 1998 Yukon hybrid
 

18. Thank you sir! I'll pick some up on the way home.

Re: 1970 C-10 / 1998 Yukon hybrid
 

3/8-18 with a large flat washer

Re: 1970 C-10 / 1998 Yukon hybrid
 

that would be the size to attach the cowl panel to the body

Re: 1970 C-10 / 1998 Yukon hybrid
 

Great build, I have a friend wanting to do this. This will be a great guide.

Re: 1970 C-10 / 1998 Yukon hybrid
 

Sub'd. Welcome to the forum, I'm going to be riding your coat-tails on this one. I've got a 68 cab and a 92 C1500 that I want to splice together. I'm all eyes and ears on this one!:metal:

Re: 1970 C-10 / 1998 Yukon hybrid
 

Are you going with a short bed, conventional or an inch and a half longer?

Are you going to alter the wheelbase?

Re: 1970 C-10 / 1998 Yukon hybrid
 

X2 :metal:

Re: 1970 C-10 / 1998 Yukon hybrid
 

here you go from the OP
If the numbers I found are correct the wheelbase is 2.5 inches longer than the C-10 SWB. My body is a LWB so I was already planning to shorten my bed anyway

Re: 1970 C-10 / 1998 Yukon hybrid
 

Oops, I wasn't thinking. Thanks

Re: 1970 C-10 / 1998 Yukon hybrid
 

No problem your project is looking good. A friend just wrecked his 99 tahoe and that has my son thinking about the same conversion for his 72 I told him lets do it.:metal::metal::metal:

Re: 1970 C-10 / 1998 Yukon hybrid
 

Thanks guys for your comments and input. I got the pedal / column bracket welded in. I hung the brake pedal and slid the seat in to check the seating position. It feels fine and the extra leg room is nice. I hope to make some brackets to mount down the front clip this weekend and bolt the backs of the fenders to the cab to get everything lined up.

Re: 1970 C-10 / 1998 Yukon hybrid
 

I'm amazed at how quickly your projects come together.

Re: 1970 C-10 / 1998 Yukon hybrid
 

Wow. I was wondering about that legroom, you have made an improved product and with the perimeter frame gas tank, you now have cab room galore.

I'm still trying to figure some things out. I do not intend to use the wiring harness on my 92 and intend to retain the stock 72 gauges. I intend to use a TPI computer/harness, probably a painless harness as the stock harness is so COMPLICATED. We'll see on that if I'm willing to buy a new harness then there is nothing to lose if I hack up the old Camaro harness. I figure I will need a speed sensor at the trans. Right now I'm running an MEFI3 adapted into the stock harness and an adaptor in the engine bay for the ramjet style fuel injection. It would be nice to keep the 92 tank (has the high press FI pump) and the rear spare tire/wind-up, then the cab tank goes buh-bye and I have a safer tank that in cab OR rear mount and get to keep my spare tire out of sight. And the 700R4 is nice with the 3.73 gears. I would have to live with the leaf springs. I assume you have coil springs in the rear.

I want to see how you do the core support; I want to retain the 72 core support if possible.

I found pictures of where a guy did the same thing kinda only he kept the early model cab intact. However, it was a 4WD so he was able to raise things the proper amount and made custom cab brackets. I'm not sure by my initial measurements if I can do that with a 2WD, in particular in the gas tank area.

Also, I see these later model frames (like my 92) have a "slip joint" assembly the factory used to simplify the production line near the front of the frame. IMO that would make shortening the frame much more feasible as my driveshaft yoke actually hangs out the back of the trans 2.5" giving me about 1.5 inches I could shorten it, that gets me close. I'm hoping to use the 92 stepside bed with modified rear wheel openings but not sure I may have to get another bed.

Now that you have modified the firewall, is there anything you would do different? Are you going to lose the stock 72 glove box area, or are you going to modify it?

Re: 1970 C-10 / 1998 Yukon hybrid
 

So you have a Camaro TPI engine in a 92' chassis? That looks impressive. Does your 72' Have A/C? I don't think I'd buy a high dollar wiring harness. I made my stand alone harness from the factory Corvette harness when I built my 911. I just laid the harness out and using a pinout diagram I started pulling out the wires I wasn't gonna need. I ended up with a handfull of wires. Switched, constant power, ground, fans, fuel pump, tach. Not a bad deal at all. Much easier than you might think.

I think the hardest part of my build will be the cowl / air box intake area. I've settled in on using the floor of the Yukon box to fill in the gap between the Yukon firewall and the C-10 air box. My new firewall will have a bumpout on the passenger side to house the fresh air intake and hold the coolant overflow tank. I'm planning on using the Yukon wiper setup so I can get the interval wipers and get the wiper setup out from under the dash.

Re: 1970 C-10 / 1998 Yukon hybrid
 

Sorry for the mis-communication. It's not a Camaro engine, it's a 350HO 330HP crate engine with a Mercruiser (what Ramjet 350 is based on without the GM Performance logo) MEFI3 upgraded to 02 and IAT feedback. It's not well calibrated (I have to dilute fuel with E-85) and it does not control EGR or TCC. The MEFI3 is wired to an adaptor that plugs directly into the 92 C1500 harness and the TBI wires have been spliced into 8 injectors that batch-fire. Ceramic coated tri-y headers have an EGR built in and I'm using external plumbing to the plenum.

I have an 86 TPI computer, harness, MAF and all the sensors; I want to use it to control it so I will have EGR, TCC, and canister purge then I can run just plain gas. I have the equipment to burn the TPI chips (used to have an 88 formula TPI 350), and I'm too cheap to buy the set-up to calibrate the MEFI3; it won't control everything I want anyway. I've been too lazy to install it because I want to do it when I do the cab change. I think I have room for the MAF next to the air cleaner, so the MAP will just be a dummy after that on the intake. Obviously I want to keep the fuel pump system intact as it's already converted to PFI pressure.

I got all the pin-out diagrams on the TPI system and I recently picked up a Packard wiring repair kit with all the connectors and crimper, so I'm more ready to dive into it. I plan on only using the wires I need to keep the computer happy and the FI and use the stock 72 C10 harness for everything else except I'll need to power the rear only anti-lock brakes. I may try to use the steering column so as to use the cruise control, intermittent wipers. I got some planning to do and then a lot of work.

The body on the 92 is all beat up from the Great Arizona Hail Storm of 2010, paint peeled, blow-out damage on the bedside, busted windshield and brittle, busted all to heck plastic dash.

My 72 C10 is factory A/C, however I would like to somehow use the A/C unit from the 92 but not sure it's possible. For sure I'll keep the R4 compressor, and if it ever fails it gets a Sanden. I may have to use more of the 92 wiring than I was thinking, shoot probably most of it. I may just re-route some of the wires and just rob the connectors I need from the 86 harness.

If you have any more pictures of the firewall work I'd love to see them. I think I will for sure have to do something similar.

Re: 1970 C-10 / 1998 Yukon hybrid
 

BTW, that orange GMC is just a rendering of what I want my 92 stepside bed to look like with rounded fender openings to match the front. ;)

Re: 1970 C-10 / 1998 Yukon hybrid
 

I assume the cab had to mount that far behind the Yukon firewall in order for the front fenders to center on the Yukon chassis?