1968 GMC - Ol' Blue

[Jason Banks]

I guess I got lucky with the bumper bracket holes on my coil spring rear end 1968, cut the 8 inches off the back. There were already 2 sets of holes on the sides of the frame, ones at the back and another set 8 inches forward. So, when the 8 inches was gone they holes were still there. Had to drill the top of the frame though.

[MDPotter]

Originally Posted by Jason Banks

I guess I got lucky with the bumper bracket holes on my coil spring rear end 1968, cut the 8 inches off the back. There were already 2 sets of holes on the sides of the frame, ones at the back and another set 8 inches forward. So, when the 8 inches was gone they holes were still there. Had to drill the top of the frame though.

I've come to realize just how much better coil spring trucks are vs leafs. For the reason you mentioned as well as a few others.

[1971Stepside]

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.

I think I can remove the last cross member behind the tank and get to all of the bolt heads if worse comes to worse. Then reinstall the cross member.

[rodstored-72]

Md potter,
thank you for the PM replies, I hope I didn't hijack your thread. As always enjoy the updates from you..

[MDPotter]

Originally Posted by rodstored-72

Md potter,
thank you for the PM replies, I hope I didn't hijack your thread. As always enjoy the updates from you..

No problem man, glad you're enjoying!

[rodstored-72]

Mdpotter,
Thanks for the info. I did have Brendan reflash my ecm. I will look again at his site (LT1Swap) ... I get focused on one info point and forget to look other places.... LOL
... thank you again

[MDPotter]

I did it - I bought HPTuners. I'm now entering a whole new level of technology. I've always hid this misconception that tuning is hard to learn and get into, but it's not that expensive and I'm slowly learning thanks to gregski's post in the LSX thread. I plugged it into my daily last night to play with but I'll hook up to my 68 tomorrow to see how it's running and how the mail order tune is working.

[1971Stepside]

I've paid a shop a pretty good sum and mine still isn't even close. I'm about to try it myself. Let me know what you think. My truck will idle great, but if you try to give it gas it loads up and dies. Way too rich. I'm not sure I can even drive it up on a trailer at this point.

[MDPotter]

Originally Posted by 1971Stepside

I've paid a shop a pretty good sum and mine still isn't even close. I'm about to try it myself. Let me know what you think. My truck will idle great, but if you try to give it gas it loads up and dies. Way too rich. I'm not sure I can even drive it up on a trailer at this point.

Mine runs great (it starts, idles, runs down the road) but I have no idea if it's running lean or rich. I'll plug it in tomorrow and see where I'm at and then start making adjustments. Gregski's tutorial doesn't address tuning for a cam swap and I'm not sure if he's planning on it or not. The only reason I got a mail order tune is because of the cam swap, otherwise the basic swap changes would have been fine (delete VATS, rear O2's, cats, etc.). At this point I'm considering the mail order tune a base tune and as long as there's nothing catastrophic that leads me to put a stock tune back in and start over, I'll use it as a starting point.

[MDPotter]

Again, spent half the day just mocking up and getting the bed skirts fitted. The passenger side was way off and I ended up cutting it in two and redrilling both holes where it mounts to the bed sill. Also had to rebend in a few spots. The driver side was much better, but still had to cut it in two and weld back together.

Then we routed the exhaust back from the mufflers to the back corners of the bed. I still need to put a hanger on it, but I plan on attaching to the frame and it's a lot easier to do that with the bed off and we ran out of time for that. I had no idea how much quieter it would be with the tailpipes ran, it's almost too quiet. These mufflers are advertised as the 2nd most quiet mufflers Black Widow makes and after installing them last fall I was surprised at how loud they were. But now with the tailpipes ran they're about half as loud. You can actually be cruising and talk to eachother, but when you step on it it's got a good sound. Let me tell you, having a lift is pretty nice. My dad has wanted one for a long time and we're loving it.

Also hooked up my HPTuners and logged some data. From my very limited knowledge of tuning, it appears to be running pretty well.

[TA_C10]

Man, how nice would that be, a lift

Looking good under there!

[sprint_9]

Good work on the inner skirts. For whatever reason that was one thing that drove me nuts on mine.

[MDPotter]

Not a big update this weekend - only had a morning to work on it. The exhaust is finished, except for tips. I fabbed up a bracket to hang it from the frame over the axle. We also replaced the fuel lines. I am convinced that the Russell rubber hose emitted fuel vapors because I would get whiffs of it while working underneath it. I replaced it with Earl's Vapor Guard hose but won't know for sure if it's better until I park it in my 2-car garage.

I can't seem to take a picture that accurately depicts just how vivid this color is.

[cornerstone]

If its more vivid in person it would be hard to see anything else. My eyes lock on to the brightness of the blue, dare I say it almost has a neon affect.


I am using the Russell fuel line and push to connect fittings. What kind of fittings do you have? Is the Earls vapor guard hose any easier to install than the Russel? It gave me fits getting the hose to seat on the PTC fittings! I may need to change over also if I smell gas in the future.

[MDPotter]

Originally Posted by cornerstone

if its more vivid in person it would be hard to see anything else. My eyes lock on to the brightness of the blue, dare i say it almost has a neon affect.


I am using the russell fuel line and push to connect fittings. What kind of fittings do you have? Is the earls vapor guard hose any easier to install than the russel? It gave me fits getting the hose to seat on the ptc fittings! I may need to change over also if i smell gas in the future.

This is a more accurate picture - this is actually the picture I saw that made me want this color.

Mine were probably the same as yours, Push Lok. The fittings had three barbs and I had to heat the hose and oil the fitting to get the hose on. The Earl's fittings are much easier to put together, just put a little oil on the fitting, slide the hose on, and clamp it. No leaks so far.

Vapors wouldn't be an issue if my truck weren't going to sit in my 2-car garage. It's been in my dad's shop which is much larger and isn't connected to the house. I never smell it there unless I'm under the truck pretty close to the fuel line. But he has the same hose on his 64 and I parked it in my garage one night and it stunk up the garage and crept into the house.

[TA_C10]

Love that color man. Looks fantastic. And that is an interesting path to route your tailpipes I assume you ended up this route because of your leaf springs?

.

[MDPotter]

Originally Posted by TA_C10

Love that color man. Looks fantastic. And that is an interesting path to route your tailpipes I assume you ended up this route because of your leaf springs?

.

Thanks! The leaves weren't the issue, there just wasn't much room over the axle. I had the axle to frame brake line, fuel lines, and the tank to work around I didn't want to have wrap the exhaust to make it work or do any crazy bends.

[cornerstone]

Originally Posted by MDPotter

Thanks! The leaves weren't the issue, there just wasn't much room over the axle. I had the axle to frame brake line, fuel lines, and the tank to work around I didn't want to have wrap the exhaust to make it work or do any crazy bends.

I went with all the crazy bends and it is tight for sure. If I ever need to do it over or it rubs/ burns anything, I'm gonna do it like yours. I've seen many that way. Very clean.

[sprint_9]

Looking good.

[MDPotter]

Hope everyone had a great Easter!

So I knew the fans that came on my radiator were cheap and destined to be replaced soon so I went ahead and did it. I bought this radiator and fans on eBay and the fans were advertised as 1,228 CFM each. Through some research, I found them on Amazon for $20 a piece from a company called UPGR8. I compared them to a Spal fan rated at 1,200 CFM and noticed that the Spal fan pulls double the wattage and that confirmed for me that they are falsely advertised. Interesting that the eBay seller has since revised the details in the item listing to not indicate any fan CFM. So anyway, I bought these Spal fans rated at 1,451 CFM each. Wired them up, worked as they should and definitely moved a lot more air. It took several minutes at 3,000 RPM to get the engine up to high temp for both to kick to full speed. I noticed that running them full speed that the volt meter would drop by about 1 volt (down from 14) and the fans would slow a little bit for a couple seconds, then return to normal. This happened every 10 seconds or so. I'm not sure what's that about, but later that day I stumbled on some info on the internet saying that Spal fans are not supposed to be ran at half speed/half voltage. I wanted to hear it from Spal so I called this morning and sure enough, the tech rep indicated that it would "prematurely" wear out the motors running them in series. So I guess I'll be rewiring my fans so that one fan is on full speed when the engine reaches low temp and then the second fan kicks on at high temp (also A/C high pressure). This is the case for Spal fans, but I don't know about other manuf's. I just assumed that this would be okay since GM does it, but the fans GM uses must be designed for it. So we enlarged the holes in the shroud and I was happy with the fit and quality of these fans.

Also replaced the front shocks due to the increased drop from where I had it originally.

I'm getting dangerously close to starting the bodywork/paint process on my bed. We got the fuel filler door mocked up. I'm not 100% happy with the door, I didn't realize that the holes drilled in it end up inside the hole you cut in the bed. I think the door is meant to be installed in wood where you can router out a recess like for the Boyd fillers. So we had to fab up some spacers and a backing plate to attach underneath. I get tunnel-visioned and forget to take pictures sometimes, so I'll take more when I install the door. I might end up putting on the poke-through filler cap so I don't have to unscrew the cap every time. Finished the day out scuffing the underside of the floor so I can epoxy the bottom side next weekend and then Raptor line the top side in two weeks.

[Camaroguy]

Originally Posted by MDPotter

Hope everyone had a great Easter!

So I knew the fans that came on my radiator were cheap and destined to be replaced soon so I went ahead and did it. I bought this radiator and fans on eBay and the fans were advertised as 1,228 CFM each. Through some research, I found them on Amazon for $20 a piece from a company called UPGR8. I compared them to a Spal fan rated at 1,200 CFM and noticed that the Spal fan pulls double the wattage and that confirmed for me that they are falsely advertised. Interesting that the eBay seller has since revised the details in the item listing to not indicate any fan CFM. So anyway, I bought these Spal fans rated at 1,451 CFM each. Wired them up, worked as they should and definitely moved a lot more air. It took several minutes at 3,000 RPM to get the engine up to high temp for both to kick to full speed. I noticed that running them full speed that the volt meter would drop by about 1 volt (down from 14) and the fans would slow a little bit for a couple seconds, then return to normal. This happened every 10 seconds or so. I'm not sure what's that about, but later that day I stumbled on some info on the internet saying that Spal fans are not supposed to be ran at half speed/half voltage. I wanted to hear it from Spal so I called this morning and sure enough, the tech rep indicated that it would "prematurely" wear out the motors running them in series. So I guess I'll be rewiring my fans so that one fan is on full speed when the engine reaches low temp and then the second fan kicks on at high temp (also A/C high pressure). This is the case for Spal fans, but I don't know about other manuf's. I just assumed that this would be okay since GM does it, but the fans GM uses must be designed for it. So we enlarged the holes in the shroud and I was happy with the fit and quality of these fans.

Also replaced the front shocks due to the increased drop from where I had it originally.

I'm getting dangerously close to starting the bodywork/paint process on my bed. We got the fuel filler door mocked up. I'm not 100% happy with the door, I didn't realize that the holes drilled in it end up inside the hole you cut in the bed. I think the door is meant to be installed in wood where you can router out a recess like for the Boyd fillers. So we had to fab up some spacers and a backing plate to attach underneath. I get tunnel-visioned and forget to take pictures sometimes, so I'll take more when I install the door. I might end up putting on the poke-through filler cap so I don't have to unscrew the cap every time. Finished the day out scuffing the underside of the floor so I can epoxy the bottom side next weekend and then Raptor line the top side in two weeks.

Attachment 2002133

Attachment 2002134

Attachment 2002135

Attachment 2002136

I did a similar door on a wood floor truck we built a couple of years ago (link at bottom). It's definitely designed to sink into the wood. We added a little arm to the fuel cap to make it easier to unscrew since the opening is so small. Good progress on the truck!

[sprint_9]

That is good info on the Spal fans. I had kind of wanted to rewire mine to a half speed setup, guess that's one project off the list.

[MDPotter]

Originally Posted by sprint_9

That is good info on the Spal fans. I had kind of wanted to rewire mine to a half speed setup, guess that's one project off the list.

Yeah, I'm glad I stumbled on that info and verified. I guess it depends on the manuf whether they are 2 speed or not.

[AlexBC]

Holy Crap! You did an incredible job! I wish I had 1/10th the patience you have to do the body work. What a beautiful truck!!!!

[rodstored-72]

md,
very nice job on the fans and the CFM verification. I purchased my radi/fan setup from summit. supposedly the fans indicate that their CFM is equal to what the factory fans did for my engine. I will also wire mine up to do the same as you indicated - first fan on full until temp/ac comp. kicks on and then kick the 2nd fan on. thanks for the build updates!!