Chopping a '51 cab 6"

[RedneckRodder]

After looking for a write up on chopping these cabs, all I was able to find were guys that had done chops around 3", which basicslly didnt do me much good, so I figured I'd make one for those looking for info on the "radical" chops.

So here's the story: I tried to chop this cab about 2 years ago, and let's just say I botched the job. I originally wanted to chop this cab just to say I could. Kind of wanted to prove to myself I could do it. But now I'm fairly certain I want to put this cab on my truck, that's why I decided to tackle it again.

So, since the weather has been less than desirable here in the Pacific Northwest recently, I decided to bring the cab back out from the barn and tackle the "repairs" properly.

Hre's what I figured out I did right, and wrong, the first time:

With a chop of this magnitude you have to split the roof from front to back, and from side to side (IF you don't want to lay the A-pillars back). I did split the front half through the center of the windshield, I did not split the back half, choosing instead to spread it. This created a situation that took me quite some time to figure out, because the curve above the door wouldn't come anywhere close to lining up from front to back. This problem is basically where I decided to put it away for a while and think it through, for about 2 years. I finally came to realize that by splitting the front and spreading the back I basic all flattened out the rear curve, while leaving the front fairly close to stock. That was my problem!

Here is the cab, after removing the back half. I didn't take any pictures of the screwed up job, but trust me, it wasn't pretty.


So, after sitting down at the drawing table for a while, I decided to find another cab to finish this one properly. I found a '48 cab from a guy who part out AD's as his retirement job.

Its a rusty piece of junk, but the roof is good, so I brought it home to make some donations to my project.

[RedneckRodder]

So I cut the doner cab through the floor and the A-pillars and drug it into the shop to scavenge what I needed from it. I started by drilling all the spot welds around the rear window and the interior back and corner panels.


Then I removed the interior panel.

I then flipped the cab back up into the upright position to scribe my cuts out BEFORE cutting anything. I decided I want to keep the rear window as large as possible, so I removed 2.75" below the window and cut out the entire window opening before removing the rear portion of the roof.

[RedneckRodder]

So, after removing the rear roof section I split it from front to rear and placed it on the chopped cab. I made sure I left enough when I cut from door to door that I could flange the front edge of the rear roof under the front section. I made sure my door openings were correct and lined up properly, drew some lines and flagged the "flat" section of the roof. I decided not to try to flange the curved section so as not to screw up the curve over the door.......... Again!


It took some work, but I eventually got it all flanged and clecoed into place.

The back section of the cab wanted to hang down, because of the unsecured weight, so I used a piece of scrap and some cleco's to set the gap and align the crown properly. This took some doing, but I found the using vice-grips to clamp a straight edge on the window opening helped quite a bit to get everything lined up.

[RedneckRodder]

Here's a better view of the back. Crappy cellphone pic, but this shows the progress. My plan is to bend up a filler piece and flange it 2" wide, and open up the gap between the 2 panels to 2". This will help fill the gap, and add support to the roof. I've learned to flange anything I can during this process, as everything seems to want to sag when butt-welded without support on all sides.


That's pretty much where I am right now, I'll update this as I go.

[RedneckRodder]

Tonight I opened up the center of the 2 rear roof sections to 3" to to make adding the center strip a bit easier. I took about 6" from the old rear roof section and flanged it 1.5" from each side, leaving a 3" raised section in the middle to match up with the cab skins. I got it all formed and clecoed into place tonight.

[alaska gasser]

Check out the link in my post. I chopped mine 6 1/2 in the front and 4 1/2 in the back.

[RedneckRodder]

Originally Posted by alaska gasser

Check out the link in my post. I chopped mine 6 1/2 in the front and 4 1/2 in the back.

I've seen your build, you've got A LOT of time and effort into that thing. I'm not usually a fan of the angled chop, but you really nailed it.

[alaska gasser]

Thanks. You are going to have a lot in yours too.

[RedneckRodder]

Spent some time above the passenger door tonight getting everything lined up and closed in.


I also decided to replace the rockers while I have the back panel removed.

[RedneckRodder]

I got the beltline section of the roof removed and cleaned up. Doesn't look like I'll have too much fitting to do. I don't want to get too carried away with this until I get the new back panel installed. Its hard to not continue working on it right now, but I know I'll screw something up if I don't wait, so I'm trying to be patient for now.

[RedneckRodder]

I got the driver side rocker installed today, looks pretty good, and it went about 3 times as fast as the passenger side did and I'm happy with it.



Welds turned out pretty nice. Not continuous beads, but it looks like it.