1972 GMC Using 2003 Chevy 2500HD duramax Chassis

[1tonwannabe]

This is my first post.
I have a 1972 C2500 Sierra Grande. I had a couple ideas for the truck in the beginning, but I new I at least wanted a 4wd. I eventually came across a rolled 2003 Chevrolet 2500HD with a Duramax/Allison with 100,000 Miles on it. In the long run I thought it would be cheaper since it ran. Otherwise I would have to drop about $4500 in a motor, about $1000 in a trans., and $500-$1000 in each differential that I had. This 2003 chassis didn't need all that. The price of the truck was $6700 on ebay. This was a steal from what I've found in the past. I bought the truck and had it shipped to Ohio.
Basically what I have now is the makings of a pretty Bad Ass tough truck. It will get around 20 MPG. or better according to some of you. I can tow anything with it. If it's built the way I want, then it will have a lot of modern conveniences, but still have the cool body of a 67-72. I plan 0n trying to use everything. I am putting the 72 on the 2003 chassis. I will try to use the interior of the new truck, the gauges, steering wheel, center console, and brake pedals.
I'll post pictures as soon as I figure out how to.

[Chevy1TonFun]

I'll be watching this one. Have fun with all the metal fab!

[1tonwannabe]

I don't think anyone will get to see it. I'm trying to figure out how to post pics. It says something about making an album. The help section of this site sucks. Says go to control panel which I did and the next step after that is a dead end.
Not worth my time.

[onebadbowtie]

create a photobucket account on photobucket.com then uplead your pics to that site. Then copy and paste the image codes from your pictures there to your posts on here. that is the simplest way

[1tonwannabe]

Thanks
Posted via Mobile Device

[Dieselwrencher]

Sounds like a sweet project man! Get the pics uploaded.

[birdistheword]

Sounds like a fun project. I've been looking into just swapping in a 6.2/6.5 in my 72 K-10.

[1tonwannabe]

2003 Chevrolet 2500HD That I started out with.

1972 GMC Sierra Grande I took it apart before I took a picture of it. It was complete minus the motor.

[1tonwannabe]

Here are the pics to get me started. I'll try to update everything soon. I'm fitting and welding the body mounts on the frame now. I'm a long way from the pics above, but I still have a long way to go.

[1tonwannabe]

I tore down the newer truck to just the frame and drivetrain with a saws-all.

[1tonwannabe]

The 2003 chassis is 16.5 inches too long. The way this frame is built, they slid the front part of the frame into the rear. So all they had to do was make one front frame that fits everything, and GM could slide in a longbed frame, or a shortbed, or a crewcab etc. in the rear. All I did was remove the factory weld where the front and rear frames join and sepperated it.

[1tonwannabe]

Almost forgot. I did not cut any wires. What you are left with is a giant pile of wires.

[1tonwannabe]

Sorry about picture quality, they were taken with my phone.

[1tonwannabe]

After I removed the 16.5 inches I slid the frame back together.

[1tonwannabe]

You can see in some of the pics were I braced the frame with I-beams. The frame went together very easily. I then welded the frame just like the factory did.

[1tonwannabe]

The only other things that I had to shorten were the fuel lines, brake lines, and exhaust. The flanges were cut from the exhaust by the transmission. I shortened the pipes and re-welded the flanges back on.

[1tonwannabe]

The center of the 2003 frame drops down farther than a 67-72 frame. If you put a 67-72 body on a newer frame, the cab would sit alot lower than the bed. This is the problem with doing what I'm doing.
My fix was removing the crossmembers from the bottum of the bed. This would drop the bed to the frame by about 3.5 inches. The cab will sit 5 inches above the frame, which sounds like a lot but if you look at a 2000's 2500HD truck about the same amount of frame is showing.
Your not going to see through to the other side.

[1tonwannabe]

I bought some Hummer H2 wheels and tires. The tires are 35 inches. I'll post pics later of them on the truck.

[1tonwannabe]

[1tonwannabe]

Here's a pic of the mounts I made for the body. I used 3"X3"X1/4" square tubing and cut off one side to make a U. I bought a bushing kit from DIY4X.com. Which consists of a 2" sleeve bushing, a greasable bolt, and DOM tubing. The 3" tubing I made into a U was bolted to the front body mount bolt hole. This way all I had to do was weld a locking nut to the U, and drop a bolt in the original bolt hole in the body. Then I made a bracket to weld to the bushing DOM tube. The bracket will be welded to the frame. You know you did it right when you can use the same exact bracket on the other side of the truck. I made the bracket that holds the bushing out of 2"x3"X1/4" tubing.

[1tonwannabe]

Driver side.

[1tonwannabe]

Just wanted to say how helpful DIY4X.com is. They are a lifesaver. They have all kinds of things for us DIY people.

[fakerwade]

Hey, this build sounds kinda familiar!!!

[Dieselwrencher]

Great work on it! It's looking really good!

[y5mgisi]

Awesome job man! Cant wait to see it finished!