1973 -1980 Cab Swap Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**62 Longbed** · 11-22-2014, 01:20 AM

My cab on my 75 GMC is rusted bad !!! I mean bad !! Is there a difference in a 2 wheel drive cab and a 4x4 cab other than maybe the center hump ... In which I believe some have a bolt on center hump .. any help is appreciated !!

GMC Guy · 11-22-2014, 01:23 AM

not to my knowledge, but i don't know much. i did a cab swap from a 79 to a 74, both 2wd though. I'd imagine aside from the larger center hump, everything else will bolt up.

74CustomK20 · 11-22-2014, 11:01 AM

Watch the Vin location. 78 and down on door pillar post 79 to 87 on dash. But physically it will all bolt up.

**old Rusty C10** · 11-22-2014, 12:19 PM

the thing you have to do on the newer cabs ( 81-87) is change over the wiper transmission and remove the cowl piece that is too tall for the older hood. The vin tag is the other issue. Use the chassis correct mounting kit and other than that youre good to go

Jonboy · 11-23-2014, 11:04 AM

The wiper switch moves around on the dash as well. 73-4, 75-83, and 84-up are different.

cadillac_al · 11-23-2014, 09:06 PM

You can use a 2wd cab on a 4x4 if you use a 2" body lift. That way you don't have to cut such a big hole in your new rust free cab floor.

whiskeydented · 11-23-2014, 09:37 PM

The 4x4 cab will have a hump for the transfer case too. I put a 79 2wd cab on my 78 4x and removed the transfer case hump and the bolt in dog hose from the 78. Real easy job. Just cut along the lines on the 2wd drive cab and spot weld the 4x pieces in place. I drilled holes and welded nuts on the underside for the dog house so it would be removable. I used square nuts so it would look factory.

stampy · 12-04-2014, 08:30 PM

Quote:

Originally Posted by whiskeydented

The 4x4 cab will have a hump for the transfer case too. I put a 79 2wd cab on my 78 4x and removed the transfer case hump and the bolt in dog hose from the 78. Real easy job. Just cut along the lines on the 2wd drive cab and spot weld the 4x pieces in place. I drilled holes and welded nuts on the underside for the dog house so it would be removable. I used square nuts so it would look factory.

If you wouldn't mind, could you post a few more pics of this swap? This winter I am going to try and do the same thing. I am switching the hump from a 4x 79 to a 2wd 78 cab. Thanks!

RoughKuntry · 12-18-2014, 02:00 AM

I could show you photos, 2wd cab put on 73 4x4. Only difference is cutting the whole for the shifter.

Can you use a 89 wire harness hooked up to a 86 engine? No it's not a v8.

11-22-2014, 01:20 AM	#1
62 Longbed Senior Member Join Date: Nov 2008 Location: Gresham , Oregon Posts: 588	1973 -1980 Cab Swap Question My cab on my 75 GMC is rusted bad !!! I mean bad !! Is there a difference in a 2 wheel drive cab and a 4x4 cab other than maybe the center hump ... In which I believe some have a bolt on center hump .. any help is appreciated !!

11-22-2014, 01:23 AM	#2
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: 1973 -1980 Cab Swap Question not to my knowledge, but i don't know much. i did a cab swap from a 79 to a 74, both 2wd though. I'd imagine aside from the larger center hump, everything else will bolt up. __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

11-22-2014, 11:01 AM	#3
74CustomK20 Registered User Join Date: Oct 2014 Location: Tell City, IN Posts: 637	Re: 1973 -1980 Cab Swap Question Watch the Vin location. 78 and down on door pillar post 79 to 87 on dash. But physically it will all bolt up. __________________ Big Nate Carp. Local 224. Buy made in the USA! 03 F350 6.0 Daily Race Truck. 79 C70 366 Project Dump.

11-22-2014, 12:19 PM	#4
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,313	Re: 1973 -1980 Cab Swap Question the thing you have to do on the newer cabs ( 81-87) is change over the wiper transmission and remove the cowl piece that is too tall for the older hood. The vin tag is the other issue. Use the chassis correct mounting kit and other than that youre good to go __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

11-23-2014, 11:04 AM	#5
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: 1973 -1980 Cab Swap Question The wiper switch moves around on the dash as well. 73-4, 75-83, and 84-up are different. __________________ 1974 Jimmy- 5.3/4L80e/NP241

11-23-2014, 09:06 PM	#6
cadillac_al Registered User Join Date: Oct 2013 Location: Maine Posts: 2,376	Re: 1973 -1980 Cab Swap Question You can use a 2wd cab on a 4x4 if you use a 2" body lift. That way you don't have to cut such a big hole in your new rust free cab floor. __________________ 76 Chevy K20 76 GMC K15 77 Chevy C10 77 Chevy K10

11-23-2014, 09:37 PM	#7
whiskeydented Registered User Join Date: Dec 2006 Location: connecticut Posts: 261	Re: 1973 -1980 Cab Swap Question The 4x4 cab will have a hump for the transfer case too. I put a 79 2wd cab on my 78 4x and removed the transfer case hump and the bolt in dog hose from the 78. Real easy job. Just cut along the lines on the 2wd drive cab and spot weld the 4x pieces in place. I drilled holes and welded nuts on the underside for the dog house so it would be removable. I used square nuts so it would look factory. Attached Images

12-18-2014, 02:00 AM	#9
RoughKuntry Registered User Join Date: Mar 2013 Location: Washington Posts: 238	Re: 1973 -1980 Cab Swap Question I could show you photos, 2wd cab put on 73 4x4. Only difference is cutting the whole for the shifter. Can you use a 89 wire harness hooked up to a 86 engine? No it's not a v8. __________________ RoughKuntry 73 GMC 25 HUNDRED :Sold 79 GMC High Sierra 4x4 (Ma-Duece) :Sold 99 Chevrolet LS 4.8l/5 Speed Manual 4x4 :Selling 88 Chevrolet Burban 2500 4x4 :Buying



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