3500 cab swap

[jm101]

Hello all,
First off I appreciate the time you all take to contribute to the knowledge commons. I am probably putting this in the wrong spot, so if an admin wants to move please do. I figured all I do is tow/ haul so this would be the spot for me.

I have a very clean '89 c3500 that has a very tired 7.4l/th400, I have always wished for a 4wd. I have gotten the truck stuck more than I care to admit. I found a '93 4wd 5.7l/5-speed with a rough interior/ needs paint. Both trucks have flatbeds, and I am planning to keep my current bed as it is setup just how I want.

How hard would it be to swap cabs? Same cab size and generation, so I assume body mounts and things are all same-same. I haven't pulled the carpet on the c3500, so I don't l know if there are cutouts for the shifters already, or will I need to pioneer the holes for t-case and trans shifters? Any other things I am not thinking of?

Thanks

 

[someotherguy]

Welcome,

The 89 and 93 cabs are extremely similar except for a few details. As you already wondered, you'll need to cut the holes for the shifters. Easy enough to make a template from your existing cab.

Slightly trickier will be the hole on the passenger side of the firewall where the wiring harness passes through to the ECM. In 91 the hole changed from a square with a single screw to a rectangle with two screws. There's a plastic block affixed to the harness that attaches there like a hard grommet. There's probably a few different ways you could choose to deal with this.. I haven't had to battle that particular issue before but I believe with some care, you can remove that block (it may be glued) and swap it from the other harness so it is correct for the cab you are using.

Hopefully the 93 cab has a clean title (or you can get one) so you won't be tempted to swap the VIN tag on the dash with your 89, because that's something that could end up with your truck being confiscated and you in trouble with the law.

Richard

 

[Supercharged111]

Seems like you could just keep the harnesses that match the cab and call it a day.

 

[someotherguy]

Seems like you could just keep the harnesses that match the cab and call it a day.

Enough differences in the 89 and 93 harness even if same engine.. that he'll be doing some hacking either way. I'd try to swap the block on the harness where it attaches to the firewall, if possible; as I said I haven't done it that way yet. So far my swaps have involved year models that were compatible in that regard.

Richard

 

[jm101]

Copy, thanks for the responses.
Both trucks have clean titles. I will keep chassis and dash vins matching.
Note the 2wd is a 7.4l and the 4wd is a 5.7l.
Given that I absolutely abhor red trucks, may be simpler to re-paint the white '93 and swap interior parts. Pioneering holes for two shifters and a firewall plug would be a chore. Not that paint and swapping interiors isn't, but we must pick our battles. I have't looked at the '93 yet, so much of this is brainstorming.
~JM