swithing 87 cab for 84 cab

[87 3+3]

I recently purchased an 87 3/4 ton 4x4 standard cab. The body is rusted so i have gotten a rust free bed and front clip. I have found a rust free 84 cab that came off of a 1 ton that i might buy. my question is: Will this cab bolt on to my 3/4 ton frame? My other main question is: What will i have to do to this 84 cab to make it work for my truck with my fuel injected 350 and what ever else i might have to change with the wire harness? I was told i would have to switch the wiring harness from my 87 cab to the 84 cab. Is this true or is there a different/easier way? How hard even is it to switch the whole wiring harness? I am worried it will be too much for me and i wont be able to do it, i am only in high school...

Thank you.

[Your41Plague12]

The 84 cab will bolt right up. Is the 84 cab a 4x4 as well? You need to make sure it has the high transmission hump rather than the low one. It will have the high hump if it is a 4x4 cab or a 2wd cab with a 4-speed. You will more than likely have to swap the whole wiring harness. It's not that bad, to be honest. It's really all plug and play. Unbolt the wiring harness from the engine compartment and unplug everything. You may have to cut and re-splice the rear light wires, but even if you do, it's easy. Two long sheet metal bolts hold the fuse panel to the firewall from the inside. Then just disconnect/unplug everything inside that needs to be unplugged, and swap it over. Plug it back into the engine bay harness when the cab is on the frame and you should be good to go. One more thing you may have to cut and re-splice is the dome light wiring (I had to on mine, swapping an 84 cab onto an 83 frame) but it is easy as well. Best of luck, and post some pics. We'll help you through. I just did the exact same thing, so if you have any questions feel free to ask.

[87 3+3]

Originally Posted by Your41Plague12

The 84 cab will bolt right up. Is the 84 cab a 4x4 as well? You need to make sure it has the high transmission hump rather than the low one. It will have the high hump if it is a 4x4 cab or a 2wd cab with a 4-speed. You will more than likely have to swap the whole wiring harness. It's not that bad, to be honest. It's really all plug and play. Unbolt the wiring harness from the engine compartment and unplug everything. You may have to cut and re-splice the rear light wires, but even if you do, it's easy. Two long sheet metal bolts hold the fuse panel to the firewall from the inside. Then just disconnect/unplug everything inside that needs to be unplugged, and swap it over. Plug it back into the engine bay harness when the cab is on the frame and you should be good to go. One more thing you may have to cut and re-splice is the dome light wiring (I had to on mine, swapping an 84 cab onto an 83 frame) but it is easy as well. Best of luck, and post some pics. We'll help you through. I just did the exact same thing, so if you have any questions feel free to ask.

Yes the 84 cab is coming off of a 4x4 and both my, and his truck have the 4 speed in it. Thank you for all of this info. It has helped me out a lot. I think I'm going to buy the 84 cab and take on the project. And i will post pics when i start it, especially when i get stumped. Thanks

[mrolds88]

Also, if you are worried about that harness, as you are disconnecting everything, use some masking tape and a sharpie marker to label all the connections. If you have a situation like was stated about splicing a plug (cab light) you can fish the one off the old cab into the new one. Simply tie a wire onto the old light then pull the light out. Take the light from the original cab and tie it to the wire and pull it back through. If you take your time, everything will work out. My son and I did the same thing. Had a 80 that we rewired and used the harness/gauges, etc. out of an 87. Just takes time and a bit of patience.

[87 3+3]

I am going this Saturday to help the guy unbolt/disconnect his 84 cab and buy it. My dad said he will help me do the switch as well. When i need help i will talk to you guys... Thank you for all of the help and i will post some pictures soon hopefully.