Re: 1968 GMC - Ol' Blue
 

The brown truck dropped off my drop leaves yesterday. These are advertised as 4", but comparing the thickness of the leaf stack to my stock HD leaves, I might get 5" of drop out of these. Can't wait to put these on this weekend and see where the back ends up!

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Re: 1968 GMC - Ol' Blue
 

Wow that's a big change. I would almost think it might ride better too.

Re: 1968 GMC - Ol' Blue
 

Awesome :metal:

And I agree with sprint, seems it would ride more comfortable.

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Re: 1968 GMC - Ol' Blue
 

We got quite a bit done Saturday. We swapped out the drop leaves and installed new u-bolts (the old ones were pretty cancerous). Measuring from axle to frame, it dropped about 3" which is less than I expected, but I'm happy with where it sits now. I looked at moving the upper shock mount to the rear hole, but it looks okay. We test fit a bedside and I decided to cut another 1/2 coil off the front so it sits down in the front a little bit. My dad got a new set of wheels and tires on his truck so I put his old set on my truck and they actually look pretty good.

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Re: 1968 GMC - Ol' Blue
 

Were you able to figure out the issue with the belt jumping a rib on your dads truck? Im having the same issue; belt jumping a rib on the ac compressor with kwik bracket.

Re: 1968 GMC - Ol' Blue
 

So he bought a laser pulley alignment tool (worth the money) and we checked every pulley and the only one that was out of alignment was the power steering pump. We had replaced it a long time ago but the pulley wasn't pressed on the pump shaft far enough so we pressed it on as far as it would go but still wasn't quite enough and there was actually some axial play in it. So we replaced the pump and it lined up much better and we put on a new belt and no issues so far. Whether the power steering pulley had anything to do with it is unknown, but it's running great now so we're happy.

Re: 1968 GMC - Ol' Blue
 

Thanks MD! First thing I did was check my power steering pulley and sure enough it needed pressed on. Pressed it on and fired up the truck and the belt didnt jump off. Easiest fix to date!

Re: 1968 GMC - Ol' Blue
 

Well what are the chances! Glad to hear it was an easy fix.

Re: 1968 GMC - Ol' Blue
 

The process of making an aftermarket bed assembly work has begun. We got the floor, front panel, sides, tubs, and tailgate all put together. A list of the modifications:
-Trimmed 3 out of 4 front/rear edges of tubs. They were pretty wide and were resting on the ridges in the bed in most spots.
-Elongated the holes in pass side tub where it bolts to the bedside. The whole tub needed to move about 1/4" rearward to get holes to line up with the floor.
-Elongated the top two holes in the front end of the bedsides where the bolt threads into the captive nut of the front panel.
-Trimmed excess material from the tailgate so the linkage could fold up completely.
-Cut and rewelded the pockets in the bedsides where the rear cross sill slides into.
-Elongated a couple holes in the tubs/floor so they would bolt up
-Trimmed excess material from driver bedside where front panel curl slides into the bedside.

Not trying to steer anyone away from buying an aftermarket bed, this is just a list of what I encountered and I don't think any of it is unreasonable. It's just what you have to do with aftermarket sheet metal. I still have to fit the skirts, those will take some modification too.

So we got the bed set on the truck and man are the wheel openings on these trucks huge! I'll have to do something about that down the road because these tires are way too small. I could easily fit 20's with low profile tires.

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Re: 1968 GMC - Ol' Blue
 

potter,
hi! very nice build.. I have a couple questions for you related to your fans setup. according to post #160:
"...Also got my fans and fuel pump wired up and running. I used the GM 3-relay setup for the fans so they both run half speed when the PCM calls for low-speed and they both run full speed when the PCM calls for high-speed. This is a fuse block/relay setup I got from Amazon for $30. I looked at the Bussmann setup and it's nice because it has internal bussing to make wiring a little easier, but I would have spent over $100 because there is a minimum quantity of seals and terminals so I would have ended up with hundreds of them that you don't use. This block worked pretty well - I soldered the 10 ga wires to the terminals since they weren't big enough to crimp. Other than that, the seals fit tight and I'm pretty happy with it. Don't mind the labeling on the wires, we just used leftover wiring from my AAW harness to match the colors used in the GM diagram."

did you use any of the factory wires (factory harness) for your fan connections?
if so where and how did you located or tied into them?
I am wanting to do the same setup in my '86 with a 2013 4.8 and complete factory harness.
thank you for your time & sharing your build!!:metal:

Re: 1968 GMC - Ol' Blue
 

rod - If you mean the American Autowire chassis harness, no. If you mean the LS engine harness, yes. I don't want to bombard you with information, but here is some info on what I did. I don't know anything about square body wiring, but here you go:

The wiring for the fans and fuel pump is pretty much isolated to the engine bay. Since most EFI fuel pumps and electric fans require more amps than the circuits in these old trucks can provide, I didn't use the fuel pump or fan circuit from the chassis harness. Instead I took power straight from the "disconnect" - it's where a couple fusible links separate battery power from the rest of the truck that I have mounted on the core support. Without knowing where your PCM is located/will be located, I don't know what's easiest or cleanest for you. The PCM for your LS has (3) wires which control the fans and the fuel pump - two of them are ground triggers for the fans and the third wire is actually a 12v trigger wire for the fuel pump. I reworked my own LS harness and left these three wires in the main trunk of wires that in factory form (2013 vehicle) routed to the PCM which sat in the engine bay. But when I reworked my LS harness, I wanted the PCM to be in the cab so I tore it all apart and routed the main trunk of wires down the back of the engine, on top of the trans and into the cab under the center console.

Re: 1968 GMC - Ol' Blue
 

Bed is looking good on there! Wheel wells are huge. I will probably end up with bags and 20's at some point, but that will be after she is done.

Re: 1968 GMC - Ol' Blue
 

You are a better man than me! It would be a hard pill for me to swallow if I got a bedside with a "small" dent in it like that one. I'm sure you can handle it, but I don't know if I would be able to!:banghead:

Re: 1968 GMC - Ol' Blue
 

They offered me a buydown or to send me a new one, I opted for the buydown. It won't take much work to fix it and the chances of a replacement bedside being damaged are there too. If you can swap a Gen V LT into one of these trucks, you can repair a minor dent!

Re: 1968 GMC - Ol' Blue
 

Nice work Potter, cool to see all the work your doing for the replacement parts.

Re: 1968 GMC - Ol' Blue
 

mdpotter,
Thanks for the reply. I guess what I am looking for is where the factory harness fan wires are located in the harness? I have the wiring diagrams for the engine, but I am trying to find the physical ends of the wires in the harness to connect the fan wires/relays to.You mention the fuel pump wires? are the wires for the fans in the same loom as the pump? I am expecting to see wire connector(s) for the fans somewhere in the harness all around the engine … IE: the connectors for the AC compressor … I promise I won't high jack your thread anymore.:waah:. sorry for the high jack. I like the progress you've made so far... very nice!!:metal:

thanks!!

Re: 1968 GMC - Ol' Blue
 

No worries, I'm glad to help when I can. If you know where these wires are at the main PCM connectors, you can use a multimeter set to continuity ("beep") mode and put one lead on the pin at the PCM connector and then start hunting for the other ends. If your diagrams indicate a wire color, that helps too. I don't know as much about the Gen IV's unfortunately. We had Speartech rework my dad's harness but I did my Gen III.

Re: 1968 GMC - Ol' Blue
 

lt1swap.com ?

Re: 1968 GMC - Ol' Blue
 

Yeah, probably some helpful information there too. Unfortunately Brendan doesn't have a lot of info on Gen IV's, but I would think the pinouts he has for 2008 5.3 are similar.

Re: 1968 GMC - Ol' Blue
 

One of the side effects of cutting a LWB down to a SWB is having to re-drill the bumper bracket mounting holes. It was a bit of a struggle though because of my leaf spring hangers, the fuel tank being in the way, and the bed being on but all necessary obstructions. Unfortunately it was nearly impossible to use the forward most hole in the inner bracket because the hole landed about 1/2 on 1/2 off a rivet and was impossible to access with the fuel tank in place so I opted to use the stock rear hole of both brackets and drill another hole a couple inches forward of that. This new hole goes through about 5 layers of steel (frame, leaf hanger, bracket, bracket reinforcement) so it took A LOT of drilling. Not the ideal setup, but this truck won't be going to any demolition derby's and this should hold it okay. We spent the good part of the day working on this.

Then we spent about an hour filling the stake pocket holes for that clean look.

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Re: 1968 GMC - Ol' Blue
 

potter,
nice progress! I still really like the blue:metal:!! I was wondering if you might share specifically how you wired the DBW? I am trying to do the same on my '86 c10 with a '13 4.8/4L60E setup & would very much appreciate any helpful hints or expert guidance;)!!

thanks!!:ito:

Re: 1968 GMC - Ol' Blue
 

Hard work paid off, it looks great as usual.

Re: 1968 GMC - Ol' Blue
 

I was just looking at the Boyd tank and thinking about bolting the bed down and the bumper on...looks like the tank may have to be dropped to do this on mine.

Re: 1968 GMC - Ol' Blue
 

Yeah there seems to be an order of operations with all of those components. Here are the challenges that I have encountered on my dad's (wood floor) and mine (steel floor):
-Non-existence of holes in the frame rails for bumper brackets (LWB to SWB conversion issue)
-Locating the fuel filler in the bed wood
-Installing the wood strip with the filler in it (this is a pain if you have the Boyd flush mount fill).
-Installing the bumper brackets with the tank installed.
-Installing the bed wood with the tank installed.

Maybe the order for you is bumper, tank, bed, wood? Or bumper, bed, wood, tank? It gets hard to install the hardware to secure the wood to the bed with the tank installed, but if you have enough slack in your fuel lines and wiring maybe you can drop the tank with everything hooked up and reinstall the same way?

Either way, you're on the right path with the Boyd tank. I wish I would have spent more money and bought it. If you weld the mounting strips to the frame then it makes tank removal/reinstall a breeze if you have enough slack in your fuel lines and wiring.