87 GMC 2wd cab to 78 K20 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

78K20 · 07-10-2005, 05:42 PM

I've got a 78 chevy 3/4 ton 4X4 that needs a new cab.
I bought a southern 87 GMC Sierra 2wd with no rust to use for the
new body.
I was comparing the dashes today, and noticed that the dash covers
are different. I'd like to use the old dash out of my 78 on the 87 cab.
Is the metal under the dash cover the same on both cabs ?

I'd also like to use the seat out of my 78 on the 87. Are they a
simple bolt on exchange ? I had my seat in the 78 reapolstered
in vinyl so my dogs hair wouldn't stick to it. Besides, the seat in
the 87 is cloth and has cigarette burns in it.

In fact, the truth is, I MUCH prefer the look & style of everything
on my 78 4X4 cheyenne over the 87 GMC Sierra. What I'm trying to
do is restore my 78 to look like it did before the rust belt got it.
The 87 GMC I bought is rust free, I just think it's boring in the looks
department.

Anybody done a switch like this that can give me any constructive
input ?

Thanx,
78K20

TrainD5115 · 07-10-2005, 09:46 PM

The seats should be a direct bolt in swap. I know some other people will chime in here but I seem to recall other members talking about differences in the K cab vs. the C cab. I don't know the specifics of that argument though. I believe the dash covers will interchange as long as you keep everything the same. I'm sure you can see that 87 and 78 dash parts will not mix. Hope this helps until the experts get here.

*79 silverado* · 07-14-2005, 01:31 PM

Maybe this will help? I tried putting a 78 dash pad into an 84 once for the fun of it to check if it would work or not, I was parting out the 78 and had no pad in the 84. It "almost" fit but the steel rib under the pad on the 84 got in the way of the angled part on the older dash. Now you might be able to cut or bash the edge of the sill in on the newer truck, but not something I would recommend, nor can you easily swap out those metal panels. They are bolted in on the sides, but actually are pinch welded into the lower part of the windshield frame at the cowl making up one of the layers of metal there, so damaging and distorting the windshield and mounting area are a big concern.

**Captkaos** · 07-14-2005, 03:59 PM

The physical shape/size of the metal in all cabs 73-87 never changed. A 73 dash will fit a 87 pickup and vise versa. The doors DID change. The floors on 4x2 vs 4x4 will be different due to transmission/transfercase clearance/access.

Free88 · 07-14-2005, 07:21 PM

If you like the appearance of the 78, I suggest that you look at the front ends. They are different. The 78 has a more square edge to the fender at the front edge. The 81-87 tend to round out more. Different rad cradle, grille, hood, inner fender wells. If the 78 front clip is perfect then you can bolt it on, using the wiper arms and control parts. Also a different front window cowel. Sorry if I have confused you but I am in the process of doing this swap as well. :gm2:

78K20 · 07-17-2005, 09:19 AM

Thanx for all your input guy's. I haven't had any time lately to do any
work on my truck due to my job (overtime).

I did manage to remove the bed off the 78K20. Today I'm going to
start unbolting the body on the 87 GMC.

I bought a 81-82 chevy truck grill to replace the ugly GMC grill. I still
would rather use my 78 front clip, but the core support needs metal
replacement @ the bottom below the battery tray, @ the hood is shot.
I'm hoping the trans tunnel from the 78 will unbolt @ re-bolt to the 87.

If anyone cares to have a look-see, I'll try to post some images.

I've got one of the 87 on the car trailer when I got back from Tennessee.

beaterC10 · 07-17-2005, 05:08 PM

Quote:

Originally Posted by 78K20

I bought a 81-82 chevy truck grill to replace the ugly GMC grill. I still
would rather use my 78 front clip, but the core support needs metal
replacement @ the bottom below the battery tray, @ the hood is shot.
I'm hoping the trans tunnel from the 78 will unbolt @ re-bolt to the 87.

The 4wd drive tunnel will not bolt direclty into the 2wd, I found this out the hard way. The 4wd floor pan has a flattened area that the cover bolts to that is not present in the 2wd. The other difference is at the cover rear attachment point. Again the 4wd tunnel has a flat area to bolt the cover to. You can bend the 4wd cover flanges down to mate to the 2wd tunnel, along each side, but you will have to do more creative work at the rear.

78K20 · 07-17-2005, 10:35 PM

Great............more work to do.

Got the front clip & cab off the 87 today.

07-10-2005, 05:42 PM	#1
78K20 Registered User Join Date: Apr 2005 Location: LaPorte, Indiana Posts: 109	87 GMC 2wd cab to 78 K20 I've got a 78 chevy 3/4 ton 4X4 that needs a new cab. I bought a southern 87 GMC Sierra 2wd with no rust to use for the new body. I was comparing the dashes today, and noticed that the dash covers are different. I'd like to use the old dash out of my 78 on the 87 cab. Is the metal under the dash cover the same on both cabs ? I'd also like to use the seat out of my 78 on the 87. Are they a simple bolt on exchange ? I had my seat in the 78 reapolstered in vinyl so my dogs hair wouldn't stick to it. Besides, the seat in the 87 is cloth and has cigarette burns in it. In fact, the truth is, I MUCH prefer the look & style of everything on my 78 4X4 cheyenne over the 87 GMC Sierra. What I'm trying to do is restore my 78 to look like it did before the rust belt got it. The 87 GMC I bought is rust free, I just think it's boring in the looks department. Anybody done a switch like this that can give me any constructive input ? Thanx, 78K20

07-10-2005, 09:46 PM	#2
TrainD5115 North Coast, baby! Join Date: Jun 2004 Location: Toledo, OH Posts: 437	The seats should be a direct bolt in swap. I know some other people will chime in here but I seem to recall other members talking about differences in the K cab vs. the C cab. I don't know the specifics of that argument though. I believe the dash covers will interchange as long as you keep everything the same. I'm sure you can see that 87 and 78 dash parts will not mix. Hope this helps until the experts get here. __________________ Brad 79 Scottsdale C20 350/350 3.73's Still running full CA smog gear!

07-14-2005, 03:59 PM	#4
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	The physical shape/size of the metal in all cabs 73-87 never changed. A 73 dash will fit a 87 pickup and vise versa. The doors DID change. The floors on 4x2 vs 4x4 will be different due to transmission/transfercase clearance/access. __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

07-14-2005, 07:21 PM	#5
Free88 Registered User Join Date: Jan 2004 Location: Northwestern Ontario Canada Posts: 359	If you like the appearance of the 78, I suggest that you look at the front ends. They are different. The 78 has a more square edge to the fender at the front edge. The 81-87 tend to round out more. Different rad cradle, grille, hood, inner fender wells. If the 78 front clip is perfect then you can bolt it on, using the wiper arms and control parts. Also a different front window cowel. Sorry if I have confused you but I am in the process of doing this swap as well. :gm2: __________________ 1986 Silverado Short box fleet side. project 2005 VW Tiguan 4 Motion 1997 Blazer S10 4x4 1990 Chevy Silverado K1500 Extended long box

07-17-2005, 09:19 AM	#6
78K20 Registered User Join Date: Apr 2005 Location: LaPorte, Indiana Posts: 109	87 GMC 2WD Cab to 78 K20 Chassie Thanx for all your input guy's. I haven't had any time lately to do any work on my truck due to my job (overtime). I did manage to remove the bed off the 78K20. Today I'm going to start unbolting the body on the 87 GMC. I bought a 81-82 chevy truck grill to replace the ugly GMC grill. I still would rather use my 78 front clip, but the core support needs metal replacement @ the bottom below the battery tray, @ the hood is shot. I'm hoping the trans tunnel from the 78 will unbolt @ re-bolt to the 87. If anyone cares to have a look-see, I'll try to post some images. I've got one of the 87 on the car trailer when I got back from Tennessee. Attached Images

07-14-2005, 01:31 PM	#3
79 silverado Account Suspended Join Date: Nov 2004 Location: Rhode Island/Vermont Posts: 583	Maybe this will help? I tried putting a 78 dash pad into an 84 once for the fun of it to check if it would work or not, I was parting out the 78 and had no pad in the 84. It "almost" fit but the steel rib under the pad on the 84 got in the way of the angled part on the older dash. Now you might be able to cut or bash the edge of the sill in on the newer truck, but not something I would recommend, nor can you easily swap out those metal panels. They are bolted in on the sides, but actually are pinch welded into the lower part of the windshield frame at the cowl making up one of the layers of metal there, so damaging and distorting the windshield and mounting area are a big concern.

07-17-2005, 10:35 PM	#8
78K20 Registered User Join Date: Apr 2005 Location: LaPorte, Indiana Posts: 109	Great............more work to do. Got the front clip & cab off the 87 today.



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