70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

I picked up a 1970 Longhorn that is missing the engine, tranny, and other misc parts... I also have a 2500HD 4x4 with only 80K miles. They are both 133" wheel base, so they belong together, right?. Not sure how long it will take me, but I am gonna give it one hell of a try!

Stay tuned...

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

Very cool. I'm planning to do the same build when the IL winter salt catches up to my '01 Dmax body in a few years. Post a lot of pics!

http://i105.photobucket.com/albums/m...ps1qg5ci26.jpg

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

I have made some headway, but I am horrible about posting updates... I have worked a total of three weekends on it. Here are a couple pics of my progress!

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

More..

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

As you can tell, its mostly well thought out hacking and mock up right now. Much fab work to follow...

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

Both trucks were 133" wheelbase, but to me, the front opening looks close and the rear a little too far back. Can someone post some side shots from their K20 or K30 so I can get a feel for which way I need to go? Also, I think my gap between bed and cab is too big, anyone have a measurement on that?

Thanks, Kevin

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

I would agree, it looks like the bed could move forward on the chassis a little and close the gap at the back of the cab.

Can you share some more pictures of the firewalls meshing together?

No such thing as too many pics.

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

Cool build

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

Factory duramax harness I assume since you kept 03 firewall etc?

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

Yes, the factory harness from the Duramax is my plan... I kept the 03 floor and firewall for that reason as well as keeping all the AC connections, pedal, steering, etc. I plan to put the original metal dash back in retrofitted with 03 gauges, but using 70 vents. I am headed back this weekend to work on the frame. I need to get it cleaned up and repainted before I start welding floor/firewall to cab.

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

looking great.

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

Looks like a good start in a short amount of time. If you don't mind me asking what size is that shop? I am wanting to add on to my detached and thinking about a 30' x 40'.

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

awesome build. any updates?

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

I wish... Waiting for it to get a little warmer. Got the frame stripped down and need to get painted before I get back to the body fab. I just keep picking up parts that I'll need in the future. I managed to find a guy that had nearly every piece of NOS trim for a Longhorn truck, just missing some odds and ends. If anyone has NOS upper and lower cab trim (behind the door), that's about all I'm missing.

I hope to get moving on it after it warms up. It's my dad's shop, I need to convince him to insulate and heat it. I forgot to answer Luther's question (sorry), I think it is like 56'x42'...

Regards, Kevin

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

Very interesting build , Do you have any more detailed pictures of how you're mating the cab to the other floor and firewall ?

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

I will soon... I have been working on creating a cowl that has room for the 03' wiper motor, using original wiper arms and stems. The cab sits back farther than 03 firewall, so it has to drain farther forward and out the sides. Been a struggle, but making headway. Will post as soon as I'm there working on it next.

Thanks, Kevin Johnson

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

any updates on this?

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

Very cool project! You are doing a great job of meshing the 2 cabs together too!

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

that's what I'm interested in. I'm wondering how well the firewall and floor dropped into the c10 cab.

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

Cool project, I'm in

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

You're off to a great start!! Cool build!

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

Slow for me as I don't claim to be a "body guy", luckily I have my brother to help... The cowl has kicked my butt, crazy amount of fab involved to get water to flow where it needs to go, fresh air to go to right places and have room for the 2500HD wiper motor and harness and make it work with 70 wipers and stems... I had cut on the back of the cab where it wraps around frame as the 2500HD frame is considerably wider, it needed cab corners anyway. It also needed rockers, so that is my latest challenge. I hope to get them done next weekend, then the cab will get married to the floor/firewall for the final time.

I promise when I get the 2500HD floor and firewall all buttoned up to the 70 cab, that I will take a bunch of pictures and post. I took a couple last weekend, but they don't show much. I will try to remember to take more, I know we all love photos...

Regards, Kevin

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

you're making me more nervous than confident!

Trying to figure out which way to tackle this from.

Either way- keep the updates coming. Project looks great!

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

that looks really good!!!

Re: 70' CST/20 Longhorn - 03' 2500HD LB7 Duramax/Allison...
 

Holy crap man you're scootin right on through this challenge like no tomorrow. That looks super clean and I'm not even a fan of Longhorns other than rarity. Subd for sure