66 GMC Long to Short LS Swap

[Duncan K]

Welded up a bunch of holes inside the cab. The holes from the old gun rack were pretty nasty and had pulled the metal out. I made some sheet metal plugs using the core left over from an annular cutter. Drilled the holes out bigger with a step drill and it was a perfect fit.



Getting closer to having a rust free cab. Still have to fill and bunch of holes in the floor and firewall. Then tackle above the windshield and take the roof off to rust treat and sound deaden.Hoping to have it ready for blasting in a few weeks. Can't wait to see this cab in primer!

[Captainfab]

Nice work, you are coming right along despite a little setback. That happens to all of us.

[Duncan K]

One of the holes in the floor pan for the cab mounts was way off. I had to put the cab on the frame and put the bolts and bushings in for the other three to line things up. Then I drilled up through the bushing from underneath to locate the fourth one. Couldn't resist throwing a fender on while the cab was on the frame.



Cut out and relocated the hole in the floor pan.



Cut out a bunch of plugs and filled all the unnecessary hole is the fire wall.



Got the cab flipped on its back and finished up some welding underneath. Ready to start working on the top of the windshield area and take the roof off.

[joesscamaro]

It’s looking good! Some tedious and time consuming work but it will all be worth it.

[Duncan K]

Drilled a million spot welds, roof is off. Cut off the over windshield section. Fit up the new piece from my donor cab. Ready to weld in, then some sand blasting.

[url=https://flic.kr/p/2iw6MX3]

Removed the drip rails from the pillars as well

[SCOTI]

Bunch of time consuming stuff goin' on.... Progress is progress though.

[Duncan K]

Blasted the inside edge of the roof edge and hit it with some weld through primer. Clamped the replacement piece in, got it welded up, and ground flush.



Back outside and blasted the rest of the roof. Painted both with some POR15. Installed a layer of Kilmat sound deadener and put the roof panel back on. All clamped up and ready to be welded.

[Duncan K]

Finished welding the roof back together



Pulled a bunch of dents on the back and shaved the gas filler hole.



Made trip down to the sand blast place. The cab is finally rust free!! Got it shot with epoxy primer and welded the dash in after it got a coat of primer as well.

[Duncan K]

Started on the doors, got them stripped down to the shell. I cut the outer skins off and fit up the new ones. No surprise that they don't fit. They are about 3/8" too narrow on the front upper corner. Looks like I will have to weld in a filler piece.



Repaired the passenger side fender. Cut the rusty section out. Wire wheeled inside of the brace and gave it a coat of rust encapsulator. Fit and welded the patch panel and put on a coat of filler.



Made another trip to the blasters this afternoon. Blasted the doors, core support and grill surround. was happy find the core support only needs minor rust repair

[88Stanger]

Duncan K
This is like watching an artist paint his picture. Damn fine job sir! It is great to see you do this as i will need to do alot of what you are doing here soon.
I will throw just one idea at you. For the LS stock injectors, i am not sure if you are completely stock with the LS, but i did a full build up on my "69 C10 and installed a re-built LS 5.3 with a few added goodies (ie bigger cam, better intake) and at first i started off with stock injectors and yes it runs, but not good, even after a few takes at a Dyno tune. So i sucked it up and bought a set of new injectors and oh damn! Talk about waking the sleeping giant. It idles better, runs awesome. Just a little food for thought

[66C10LB]

Thanks for the post about the door skins being too narrow. Looking at the LMC Catalogue, it indicates that the width dimension of their skin is 40 inches. Measuring my door, it should be 40 5/8 inches, so the LMC skin is an annoying 5/8 inches too small. No point ordering if that is the case.

[Duncan K]

Originally Posted by 88Stanger

Duncan K
This is like watching an artist paint his picture. Damn fine job sir! It is great to see you do this as i will need to do alot of what you are doing here soon.
I will throw just one idea at you. For the LS stock injectors, i am not sure if you are completely stock with the LS, but i did a full build up on my "69 C10 and installed a re-built LS 5.3 with a few added goodies (ie bigger cam, better intake) and at first i started off with stock injectors and yes it runs, but not good, even after a few takes at a Dyno tune. So i sucked it up and bought a set of new injectors and oh damn! Talk about waking the sleeping giant. It idles better, runs awesome. Just a little food for thought

Thanks Stranger, I post as much detail as I can in hopes that it will help others. Once I get the truck on the road and get to tuning I will likely upgrade the injectors but that is a ways down the road.

[Duncan K]

Did the small bit of rust repair needed on the core support.

[url=https://flic.kr/p/2iEj2v2][IMG]IMG_E6475[/IMG][/img]

Sprayed the core support, grill surround and passenger side fender and the inside of both doors with epoxy. Started bolting things together, its beginning to look like a truck!

[Modges'66]

Wow! That is some Super-Nice work!!!
Great Job!

[Duncan K]

After a bunch of knocking around and a relief cut I got my door skin to fit. Drilled the spot welds out and removed the door handle backing plate from the old skin. Blasted it, primer and welded onto the new skin. Put a layer of Kilmat on the inside and got it all fit up. Tacked it up and then switched to Tig to try and minimize the amount of heat I was putting into the door skin. It will still need a bit of filler to smooth it out but I am happy with how it turned out.



Moved on to the door bottom. Cut the old bottom off and started fitting up the patch panel. It fits as good as all the other ones. Lots of hammering and relief cuts so far. It's tough to fit up because I can"t reach to use the panel clamps.

[SCOTI]

Clean work. Every time I check the updates I just think "wow".

[mokelley]

Very nice work! I've enjoyed reading through your build posts.

[Duncan K]

Thanks guys, with the cab finally done it actually feels like I am making progress now.

[Notch1988]

You've had a month off now... time for updates!

[Duncan K]

The last month has been filled with set backs and frustration. I finished welding up the passenger door bottom, got it body worked and in primer.



I couldn't be happier with how the door turned out...............until I went to hang it on the truck. The inner door bottom is hitting the rocker. I measured pretty carefully but I didn't check the fit before I welded it all up. The outer door bottom is curled in at the corners and doesn't line up very well either. This was disappointing, and the thought of having to cut it up again sucks. Oh well, this is how you learn.

Now the part that really sucks. One of the body lines on the door skin does not line up, its out by 3/8". No idea what I am going to do about this. I took the door off and stuck it away where I didn't have to look at it.



I picked up a hood that looked to be in really good shape, much better than the one that came with the truck. I'm getting tired of rust repair so I thought I would save myself some work and get a better one. It had a couple different colours of paint on it.

The DIY sandblast place I usually go to is now closed due to Covid so I took the hood, grill and cowls to a shop to get blasted. The hood was full of rust and filler, actually worse than the one I had. Now I am committed to fixing this one because I paid a good chunk of change to get it blasted.

I haven't been in the shop for a few days now, no motivation to deal with these issues.

[88Stanger]

Damn fine job so far!!
I have the same issue with the cab and windshield rust. Thanks for posting how you fixed yours.

[LostMy65]

Nice work

[Duncan K]

Hood looks great sitting on the truck, too bad its swiss cheese.



At this point it is easier to fix the original hood than repair the second one. I'll use the second one for patch panels. Got started removing the braces. Also never knew that the GMC hood was different than the Chevy.

[LostMy65]

Original hood will be good.

[joesscamaro]

Duncan K, I can speak with a small amount of experience and can relate to the panel fitment issues you are running into. I have used some aftermarket parts on my truck and while it’s been nice to not have to deal with rust issues...I have more than made up that time in making them fit as they should. I made small goals for each panel and try to fix one little issue at a time. You already know this, I’m sure. Just wanted to try and give some motivation. Taking these kinds of gut punches really can be discouraging...just keep moving��