Project Large Marge - Going Full Tilt

[Just-in-credible]

Thanks guys!! I'll keep updating as she progresses! This weekend, I got the rear axle back in, and was able to see how she looks aired out. Keep in mind, the rear axle is still only temporarily bolted in, so it is not in its final resting place yet.

[Just-in-credible]

Speaking of the axle location…My plan is a bit complicated for why I want to locate the rear axle in a very specific spot, which is why I have not located it permanently yet. I want the option to put a standard 60” cab to axle flat bed on it if I want. I have been keeping my eyes open for a used one. Which is why I want to be smart about where I locate the rear axle. I want to build an exhaust stack hanger first, and then measure the 60” from the back of the exhaust, so I can still have my stacks where I put them, and bolt a bed on if I want later on. The exhaust routing is also kind of complicated. I want to tuck the exhaust as far forward (close to the cab) as I can. Originally, I had wanted to locate the stacks in front of the fuel tanks, and behind the fender. When I mocked it up, I thought that kind of looked a bit off with a big gap between the back of the cab and the stack. The main issue with moving the stack forward, is that I need to keep room to clear the fender as the cab tips up. I did a few drawings, and I figured out that I can mount the elbow for the stack up a bit higher, and I can tuck the stack much closer to the cab. I still need enough room to get my hand to the cab opening lever, so this is about as far forward as I want to go with it. The blue arc in the picture is the radius that the back of the fender travels. This is kind of what I have in mind for where I am going to route the exhaust for now.

[Just-in-credible]

I am going to a friends place this coming weekend to pick up some junk yard parts so I can keep rolling on the mock up. I will be trying to pick up a set of stacks, and a set of fenders if I can. Maybe even a new transmission if I find one that I want. It currently has a 5 speed in it, but it’s a gigantic heavy duty Spicer 5 speed that is way more than what I need, the crossmember is honestly insane. Getting exhaust past the crossmember is nearly impossible, plus, this transmission does not have an overdrive. Given that the axle I bought has 4.88 gears, I will need an OD to get cruising RPM to a reasonable level. For the time being, I am going to see if I can find a 2wd GM NV4500 and make that work. The gears should be a lot closer to what I want than the 5 speed that it currently has.

[Just-in-credible]

I'm thinking these should work okay for now?

[Just-in-credible]

Well…managed to make a pretty good haul of stuff this weekend. I ended up snagging 2 old stacks, the nv4500 that I was after, and 2 used stainless fenders.

[Just-in-credible]

I want to give marge a good bath before I pull her into the shop. Next step was to remove the old seats. I am probably going to go with some junk yard seats from a 99-07 Silverado, that way, I get the integrated shoulder seatbelt. I still need to pull the floor mat and firewall insulation, they are pretty gross from the years of unwanted inhabitants. I will probably pull the heater as well, I would think it will be full of mice too.
It has been very interesting to see what parts got carried over from previous generations. it looks to me like the heater is a standard 60-66 heater, but mounted under the dash on the passenger side. The firewall attachment is the same odd shape as the standard truck opening. The ash tray and the heater controls are 60-63 C10, but with a few minor updates. I would think I can rebuild it using easy to find parts. I am thinking there is probably something wrong with the heater, since the heater lines have been disconnected and plugged, but who knows.

One thing I may need help identifying is the steering wheel. I know I can probably just use a standard 60-66 steering wheel, But this one seems a bit bigger, and has 3 spokes. I am assuming it was probably a carry over from some other generation of trucks, but I am not familliar with anything pre 1960. If any of you out there know what that might be from, let me know.

[Just-in-credible]

Marge Finally got a bath!
As a side note, the shop that I am renting kind of sucks to get in and out of. The guy is building it as a Shouse. There is a small engine mechanic in the actual shop part, which is about 45x45. My section is only about 18x45, and is the part that will eventually be the kitchen. Which is why the access into it kind of sucks. There is a big depression directly out of my door, so I have to drive in on a bit of an angle, so it makes getting things in and out of it a bit of a challenge. Additionally, the concrete floor is significantly higher than the rest of the grade, so it takes a bit of a bump to get it above that. However, the shop is located close to my house, and I really like it, so I make it work. That explains a bit more of this whole tow bar saga.

Having said all that, I took the weekend to build myself a good towing set up for moving projects in and out of the shop and around the yard. I made the tow bar and the attachment so it can be used on other projects, and it can be attached easily either front facing or rear facing. I also put a front hitch on my flat deck truck, the idea being that I can use it as a pusher. I made the frame attachment out of some 4”x4”x1/4” angle, and the tow bar is built from 2”x2”x1/4” square tube. The tow bar can either have a chain on each end if I want to just wrap it around a front axle or whatever and tow things around the yard, or I can use 5/8” hitch pins and attach it properly. I made little frame brackets that require drilling a couple holes and can bolt onto the rear of any frame that is 34” wide, so any project of this type in the future can easily be tugged around.

[Just-in-credible]

Before I took it to the car wash, I figured I should remove the heater and everything else under the dash.
WOW…I could not believe just how packed the heater was with mouse remnants. They packed the ENTIRE THING. I was wondering why the heater was disconnected. I had assumed it was leaking(and it still might be), but after seeing the amount of junk in the heater, and how the fan was seized into the housing, I would bet it would just blow a fuse. It was probably just farmerized, it was much more simple to plug the hose than it was to pull the whole thing and fix it the right way.
Anyhow…I got all the interior stuff yanked out, and towed her down to the car wash. Much to my surprise, I can actually see that I have a chevy orange big block now!
By the time I got her all washed up, and got the hitch installed on my flat deck, it was dark, and I figured I would save myself the hassle of trying to pull it in the shop in the dark. Marge isn’t in the shop yet…but she should be very shortly.

[Just-in-credible]

You really don’t get the scale of how huge this cab is until you park something else next to it. This photo is with the air dumped out of the suspension, and it still dwarfs my Apache. Keep in mind, my Apache sits at just a hair under 7’ tall, and sits on 35” tires.

[Just-in-credible]

Also, speaking of my Apache, if any of you are looking for cartoons done of your trucks, I found a guy at a car sow recently that does amazing work. He took a few pictures, and ths is what he ended up with...AND I got a t shirt with it.

[Just-in-credible]

It seems like this took me forever to get to this point, but I FINALLY got Marge into the shop. Now the real work can begin! I know my shop is small and everything, but Marge REALLY makes the space feel smaller than normal. I cant imagine how many miles extra I have ended up walking because I needed that one tool that I didn’t bring with me out into the yard. Not to mention I am thoroughly tired of rolling in the grass. And I am even MORE tired of dropping a bolt or washer into the grass, never to be seen again.

I decided I wanted to see what she would look like with the new wheels and tires on. It looks SO good. I have the suspension aired up fairly tall in this picture, so this will be a bunch higher than final ride height. But you get the idea. Also, having the bigger wheels and tires on, and having it on a nice level concrete floor for the first time showed me that I really want to push to drop it even more than I had thought. With the small wheels, the drop was perfect. The big wheels pushed me way back up higher than I wanted. Which…is not a bad thing in the end, I ended up doing a bunch more research on suspension theory, and I learned that my original plan of using the links in the front is probably not a good one. I always wondered why suspensions don’t have the links facing forward. As it turns out, you have a lot of odd nose dive tendencies that you fight with if you put a radius arm or 4 link heading forwards. I’m just glad that I figured most of this out before I did any real fabrication on the front.

The next steps are as follows…
1) Mount the stacks for real. I want to have the stacks mounted permanently before I locate the rear axle for good. I want this because I want to be able to use a standard 60” Cab to Axle flat bed, and still run my stacks. I know its kind of odd to have your exhaust dictate where your axle is, but I promise there is a method to the madness.

2) Locate the rear axle for good, and chop the extra length off the rear of the frame. I probably have about 3’ extra right now. I want the frame rails to be the right length for an 8’ or 9’ bed if I want one in the future.

3) Mount the fenders and fuel tanks.

4) C notch the rear

5) Build the front 4 link.

[350TacoZilla]

Good work man. I've never been into the tilt cabs personally but I can appreciate the work and result. Your Apache is sweet.

[MellowYellow70]

I like this project so much

[Just-in-credible]

Thanks guys! I appreciate the kind words.
I got started on the stack mounts. SO far, I like them. This is my overall plan. I am making them out of 1”x3” x 3/16” rectangle tube. I Sketched it up quick in Fusion, and this is what I came up with. I am finding that sketching things out first is really saving me a ton of time from having to redo things that look stupid.

I got the first one tacked together and mounted up, and I can’t say I’m in love with it, but it will work. I was thinking about adding lights to the cross bar, and trying to dress it up that way, while at the same time, giving it some rigidity with little gussets, but that is a future me problem.

[dagnabbitt]

Really impressive project. I love the color of this truck.

Did you confirm that it is a 1975? It is interesting that the 1960-66 design cues were used so long, I would never have been able to guess the year.

[Just-in-credible]

Originally Posted by dagnabbitt

Really impressive project. I love the color of this truck.

Did you confirm that it is a 1975? It is interesting that the 1960-66 design cues were used so long, I would never have been able to guess the year.

Yes, I did confirm the year. There are a few interesting things that changed over the years with these trucks. Things would change here and there that matched the smaller trucks, but not necessarily the same parts from the same years. For example, the heater shares parts from the 60-63. The ignition bezel is from a 67-72. But things like the window cranks and the fuse box/bulkead is definitely 73 up. So it is really interesting to see how they reused some old stuff, but changed some stuff along the way. I do know that there was three different grilles for sure that these trucks used. I would really like to find the first series grille for it, just because I think they are significantly cooler than the later series. The first generation of these trucks had a grille very similar to the 60-61 Apache’s, and the grille surround is a bit different. Next these trucks had a grille very similar to the 64-66 c10. I woudl assume it changed in 64, but I am not 100% sure of that. The grille did not change in 67 like the smaller trucks did. I am pretty sure this style of grille was used until 70 or maybe even changed in 73, and was used until 1980. The current grille surround I have goes all the way around the grille, the early ones do not. The GMC grille was always the same, just the letters changed in 66ish to the square style GMC letters. I think some time in the early 70’s, chevy switched to the GMC grille surround, and plopped in the ugly grille insert that I have now. They also had a tall cab version and a short cab. Look at the space between the bumper and the grille in the different trucks, and you can tell the tall vs short ones. The inside of the tront fender on the tall cab trucks was a much wider lip, which I think would look cool, so I am on the hunt for a set of those fenders.

Here are a few pictures to show the difference between models.

[Bigdually]

I really like this project!


It's interesting how GM has always used parts from previous generation trucks on their medium duty trucks. To this day the trend continues, a brand new 6500 shares headlight styling with the pickups from 10 years ago.

[Just-in-credible]

One of the first things that I did this weekend was to flip my temporary radius arm to the bottom of the axle instead of the top. The issue that I was having was that the radius arm would kick the rear of the bag and bag mount up so high, it wasn’t letting my suspension down all the way. Now that the radius arm is flipped, the suspension can settle down nicely.

I spent the majority of the weekend getting the Stack hanger put together. Overall, my measurements from my CAD drawing I made worked out pretty well. I also 3D printed some jigs to hold everything square as I welded it. It was a first trying out something like that, and it seemed to work reasonably well. The first thing I noticed when I had it all together and put on the truck was that I had a bit of a twist in the frame. Which was to be expected, because I did not have the bigger passenger side wheels on the truck yet.
I put the passenger side wheels on, and took my time to level the frame front to back and side to side. This made a huge difference in how square the exhaust mount was sitting.

The next thing I realized was that I will need a few more braces than I thought to make this thing rigid. It had a lot of flex and wobble. I added a second cross bar, which stiffened it up a ton. I plan to add a second set of braces at the frame, as well as a few little knee braces here and there, and a tie back to the horse shoe on the frame. I am sure this will really stiffen the whole thing up. I didn’t quite have enough material on hand to do all of that, so I will have to order some today before I can finish it up.

All in all though…I think the stack hangers are looking pretty good! I am planning to cut the stacks shorter than they are now. They will make the turn inboard above the fuel tanks. I keep them a bit longer for now, just in case I change my mind.


I also grabbed the fenders quick to see how they look and fit, I put a couple blocks on top of the tire. I don’t want to mount the fenders until I have the C notch in the frame done. So for now, they are just sitting there. I also grabbed a fuel tank to see how it looks and where it sits. I can tell that I will have to play with the mounting height of the tanks to make everything look right, but I think the vision is really coming together!

[Just-in-credible]

I got a few more things done last night. The rear axle is officially in its new home. I still only have 2 bolts per side, but that’s good enough for now. After that, I chopped the rear of the frame. I ended up chopping close to 3 more feet off the back of the frame. It is starting to look SO good now.

Its not too often that I run across a product that I am truly amazed by. But it happened last night.

I was watching YouTube videos about cleaning aluminum. I got the tanks rough mounted, and I wanted to clean them up a little bit. I kept seeing videos for Absolute acid by bling chemicals. So I thought I would give it a whirl.

WOW…first, it cleaned the tanks up immediately. It ate the oxidization layer right off immediately. Then, I saw that I got a little overspray on the paint on the cab. I noticed that it immediately brought the old color back to life. I tried a little test area, sprayed it on, wiped it off. I was shocked. The old color came right back to life. This stuff is insane. Keep in mind that it is still a bit wet in the picture. It did dry to more of a satin than a shiny clear. But I can take care of that with a polisher. It was just so cool to see.

Next…C notch the frame.

[regan wilson]

That thing looks cool. I'm sure you will get asked (What is that?)

[Just-in-credible]

Okay internet…I need some help deciding something.

I want to do a 2 tone on this thing. And I am really struggling to decide which style I am going with. I went out to the shop and used some white masking tape to try both styles. But I am torn right in the middle on which one I like better.

Which of these two do you guys think looks better? The green on the roof top, or the white on the roof top? I popped up a poll if you guys want to vote on it.

[Just-in-credible]

I got the C notch hacked out last night. I still have a lot of work to do in order to make this thing sit down where I want it, and I have to reinforce the whole thing, but this was a great start. It felt like I was hacking out all of the frame, but I had to keep reminding myself that there is still 5” of frame left, which is more than some trucks have in total. This frame is also really thick. I am pretty sure it is 5/16” thick, and it is almost 10" tall. I'm relatively confident that it will have more than enough beef left. Even with the amount I cut out, it has a ton more strength than most normal truckframes would ever have.

The night was not exacly smooth though. I did run into a bunch of issues, but most of them all come from the geometry of my rear axle in relation to the trailing arms. When I mounted the arms in the new location, they were positioned a little bit lower than they were before. I did this for more clearance with a socket and a wrench on the inside frame rails. Having my arms lower means that they ended up on more of an upward angle towards the back of the frame. This angle rolled the whole axle forward as I lowered it. I have something like a 12 degree downward angle on the pinion, and I need much closer to a 4 degree upward angle. Having the axle rolled that far forward made the top of it sit way closer to the rest of the frame parts, so it limited how much I could lower it. It also ate up all the height for my bags. As the angle of the arm goes up towards the rear, the room for air bags decreases just because of the amount of angle. My temporary solution to keep rolling with fabrication is to just 3d print a taller block between the trailing arm and the axle. This will level my arms and at the very least, level my differential, and get my bag to the middle of its range when at ride height. Once I get the ride height exactly where I want it, and I get the new transmission in place, I can then determine the real angles that I need with my driveline, and make the real stuff out of steel.
And that is where it is going to end for the next few days. I am going to see my folks this weekend, and that is a couple hours south of where I live. There won’t be much progress in the shop until next week. I do have my other parts truck at my parents farm though, so I plan to be robbing a few parts off that one while I am there. I am going to try to snag the front bumper, the grille and the front vent, so I can see what those will look like in white.

[Just-in-credible]

Sorry for a bit of a lull in the build guys! I took the week off and headed down to Dinos Git Down in Arizona. Talk about some amazing quality builds! This is the second time I have been, and it just gets more and more insane. There are a few things I was really looking at. First, how do most of these trucks run suspension components. I really looked hard at where the link bars were positioned, and how lines were run, what kind of tabs the fabricators uses, how they ran brake and air lines, etc. It was pretty amazing to see how many ideas were in one place at the same time.

I ended up leaving the show with a couple pretty major points. First…I think I am switching to a 4 link in the rear. The more I thought about it, and the more I looked at how people do it, the more I like the idea of a 4 link over the radius arm/trailing arm that I am using right now. And second, I might do something really cool with bag placement, such as a cantilever or something cool like that. I need time for my brain to wrap around it and make a better plan before I decide for sure, but so far, it seems like a pretty cool idea.

Anyhow…back to the progress on Marge. I did make a bunch of progress before I left, I just didn’t have time to post any of it.

[Just-in-credible]

I took a weekend to rip out a bunch of the remaining things left on the frame. There was a lot of old brake lines, and brackets and such that I had to clean up. Unfortunately, this meant a lot of drilling, and grinding old rivets.
The next thing I got at was pulling the transmission. It came out relatively easily, but WOW was it gross. Mice had managed to pack the entire bellhousing FULL of junk. Just in case youre curious, the bellhousing, and the funky SAE adapter ended up weighing just under 500 lbs. The transmission was 385 lbs, the bellhousing was 95 lbs, and I am sure the clutch its self was close to the same. It was a dual disc monster of a unit.

[Just-in-credible]

Once I had the transmission assembly out of the way, I ripped out the exhaust, and the old transmission crossmember. And much to my surprise, the mice had also made their way into the entire exhaust system, and packed all the exhaust pipes FULL of junk. That was a lovely surprise to find as I was under there with the Sawzall…

Anyhow, The transmission crossmember was huge, and was not at all in the right shape or location for anything I wanted to do. So out it came. Which meant more grinding and drilling rivets. Yay…