66 GMC Long to Short LS Swap

[Duncan K]

Turns out I had my fuel lines reversed, switched them around a it fired right up! Idles better than I thought it would without tuning.

https://youtu.be/o16voQxiL0I

[SCOTI]

Sounds good.

[sstock]

Spent a lot of time going through your build thread. Congrats of bringing this truck back to life, many would of walked right by it.
Sir you have mad skills.

Steve

[Duncan K]

Back to rust repair on the cab. Finished the driver side cab corner.



Moved on to the firewall/kick panel. This part is really tricky but I learned a lot from doing the passenger side so hopefully this side goes quicker

[Duncan K]

Cut, fit, weld, grind, repeat!! Slow and steady

[Captainfab]

Coming along nicely

[SCOTI]

Originally Posted by Captainfab

Coming along nicely

x2.

[SkinnyG]

Looks a little hot. Try speeding up a bit. You kinda get the heat sweet and then boogie so you don't overheat the stainless.

Are you back-gassing, or Solar Flux?

[Duncan K]

Originally Posted by SkinnyG

Looks a little hot. Try speeding up a bit. You kinda get the heat sweet and then boogie so you don't overheat the stainless.

Are you back-gassing, or Solar Flux?

Yeah, I cooked it pretty bad at the beginning. Got my heat and travel speed dialed in a bit better on the last joints I did. Still not shiny and clean though.

No back purge, never heard of Solar Flux

[SkinnyG]

You need to protect the back of the weld. Back purge is good if you have the apparatus for it (a "T" and second regulator works well).

I've done Solar Flux B which is a powder you mix with Methanol and paint the backside - it prevents "sugaring" (looks like barnacles) and polluting the weld.

[tinydb84]

You are running too hot or too slow. With thin stainless tube I weld from 1 o'clock to 11 o'clock (I am right handed). When you run 3 to 12 it is welding up hill and building heat.

Definitely want to back purge the weld. That will help. I bought a second tank and another regulator. It was a tiny bit more expensive but now I never run out of gas on a weekend (the dual flow regulators are expensive!).

I run a #7 cup most of the time. Get a thin filler rod. You cool the puddle by adding more rod and it will absorb more heat.

[Duncan K]

Skinny, Tiny, thanks for the input!

Welds are getting a little better, but they are still not shiny. I had a cheap Chinese gas lens that wasn't sealing to the torch and was letting air mix with the argon. Changed that out for a CK lens and things improved right away.

I have a second Argon tank so I ordered another flow meter so I can back purge. Also have a Furick Fupa 12 cup coming.

[Duncan K]

I finished welding the h pipe section and moved on to the back section. Got the mufflers mounted where I wanted them. Tried a few different pie cuts and bends to get clearance from the trailing arms. Everything is tacked up ready for finish welding once my flow meter and Furick Cup arrives. The slip fit on the Magnaflow mufflers is really crappy. The diameter of the inlets on the mufflers are too big so the fit is really sloppy. I cranked the clamps down but the mufflers still wobble. The gap is probably too big to weld up so I'm not sure how I am going to solve this



Still need to make a few hangers. Not sure if I am going to just dump the exhaust out past the axle or take it all the way out the back

[tinydb84]

Good stuff! They make tail pipe expander tools though I don't know if they would work on stainless.

Can you post a pic of the fit of the tube in the muffler? You might be able to use a larger rod and walk the cup back and forth over the gap with the rod in between. Then do a pulsed cover pass to make it look nice.

[made2drag]

This build is awesome, cant wait to see more....

[Duncan K]

Back to work on the cab. Finished up the driver side floor, fit the rocker, all is great. Hung the door to make sure all the gaps were good and.............CRAP! Door doesn't fit in the opening. Looks like the front part of the floor is about 5/8 of an inch too high. Not sure what happened, there wasn't much left to measure off, everything was completely rotted out. had to cut the pillar, kick panel and across the floor, and then bend the floor down 5/8". Nothing like hacking up stuff you just finished replacing. I hung the door and what was left of the original fender to confirm fitment of the door this time. ended up having to push the rear pillar back a little as well to get the gaps right.



Pushing the floor down changed the angle of the firewall so I had to remove a piece of the kick panel to make it work. Took a lot of work to fix this mistake. Added the 5/8" to the pillar, kick panel and firewall and welded everything up, .....again!



Got the rockers welded in on both side, and patched a hole in the cowl.



This was a really frustrating mistake to make but I am moving forward again and I learned what not to do for next time.

[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.

[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