1987 GMC cab forward sheet metal on 1980 CK20 cab

[Kryptonitekid]

Hi Folks,
I have acquired a 1987 pickup for parts and I want to put the the front clip on my 1980 (call me crazy but I like the cleaner lines and dual headlights of the later models).
I looked through the threads but it I can only find posts going the other way - 80 style onto a later cab.
I am trying to account for changes that will be required to do the retrofit i.e. what will not just bolt up to the earlier cab so I don't get it apart and then find out the cab or frame would need major rework.
It appears that the major changes are the hood hinges, which should not be an issue since they bolt to the fender, the radiator mount and the windshield wiper assembly and grill.
Has any body done this or they can point me to another thread on such a project?
These are the changes I think I need:
1. Windshield wiper assemblies, wiper motor and sheet metal grill. Does the cab need to be modified to accommodate the later assemblies and sheet metal?
2. Fenders
3. inner fenders
4. entire radiator mount and headlight assemblies
5. wiring harness changes for headlights, signals and park lights
6. battery tray, cables and windshield washer tank
7. bumper frame mounts
8. Hood and hood hinges
9.radiator fan shroud and hoses
10. inner fenders
Any input appreciated!

 

[Craig 85]

I did the same thing to my 80 3+3 back in the 90's. Pretty easy swap. The two biggest issues are cutting slots in the cowl to let the hinges drop into it and cutting the front frame horns to allow the 81 & up bumper brackets to fit.

I had purchased a complete front clip. The only part I reused was my radiator. Everything bolted up. I can't recall which body mounts I used for the core support. The wiper stands for the '81 & up must be used as they are taller. The headlight harness plugged right in to the firewall and the high beams worked with my floor button.

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[bucket]

That's the way everyone used to go, now people tend to backdate their trucks.

You have to use the core support mounts that match the frame year. The mounts are in a slightly different location, but the newer core support should have enough adjustment. Going the other way, it certainly poses a problem though.

In short, every piece of the front clip is different. If your '80 has the optional taller radiator, you can reuse it.

 

[Kryptonitekid]

Thanks Craig and bucket. Great information, now I know what I need to do. Since the salvage truck is complete, I should be able to use it as a reference. Once I get it all apart, I can figure out the frame rail cuts for the bumper brackets and the cowl mods for the hood.

 

[Clif Bakx]

Sounds like an interesting swap!
Say, on a different but related note, I'm restoring my 80 GMc 1/2T, and i need two new fuel filler doors.
I bought 2 from LMC, and they are the worst! don't fit, wrong bracket as they don't flush mount, and they need a ton of body work.
I really need a couple of OEM ones, even if they need a bit of body work.
Someone have access to a couple of these?
Thanks!
Clif
204 381 7869