73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Topic started by: NC4X4SWAMPER on November 09, 2008, 07:04:09 pm
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Hello everyone, i would like to say this is a great site with a lot of good info..... My question is i have a 1981-1986 k20 3/4 ton long bed frame with a dana 44 front axle and 14 bolt rear axle with a 4" suspension lift and i was wondering if i can put a 1977 2wd long bed body and bed on this frame and if so what if any modifications would have to be made?
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Welcome to the site, I will leave the ? to the experts. I do know it is a fairly easy swap.
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If its just the frame it will work, the floor will be needed to be modified for the transfer case and the body mounts you`ll need the 81-7 cause of the frame body perches (73-80 frame perches are different)and other than that it should be adirect bolt on.
thanks
pat
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Welcome to our Chevy family from New Hampshaa.
You will need to cut the floor center section out of your 4x4, Cut it bigger so you can use 1/4 self tapping screws to hold it down in the new cab. Cut 4x2 center section out of the 77, there is an indentation all the way around you can use for a guide. Replace it with donor piece. I use butyl tape or the tape for metal roofing that goes between the panels on the over lap for a sealant under the floor center section. The floor center section out of the 73 - 80 4x4's are bolted in. If yours is not useable you could round up one of them. Also the 73 - 80 front bumper mounts are different. you might need to do a little bit of fabricating some brackets to fill the space between the newer frame and the older bumper. The frame horns on the newer trucks are trimmed back at an angle for the angle of the bumper. I would reccomend using the entire 77 wire harness to avoid little issues there. Depending on the exact year of your chassis there are a few things to think about. If its a single tank the filler door might not be on the correct side? You will need the 77 filler neck and hose if I am not mistaken I think they still had a spin on fuel cap? If its dual tank bed it won't bother any, if your Chassis is duel tank , and the body isn't you will need to wire up your dual tank switch, and add the second filler. The wiring for it passe through the fuse box / bulkhead connector. You might have to mix and match the e brake cables. Somewhere along the cable it will have to go from the 77 to the 80's style. The older ones go back to about the tail shaft and cross over for the right hand side. The newer ones cross over at the rear axle. Are both truck automatics, or sticks? If they are autos the newer one 82 / 83 or newer could have had a 3 or 4 speed auto. If its a 4 speed auto the shift indicator will be off. If they are both sticks and the chassis is 85 or newer you will need the clutch pedal, the pedal linkage to the master cylinder, and the master cylinder to swap into the 77. Or switch the chassis over to a non hydraulic bellhousing. If the 77 is a stick and your is an auto, you are going to need an auto column for the 77. If your high beam etc. is not on the column ( up to 83 if I remember correct ) you could use it but you will have to work out a little bit of wiring issues with the 77 under dash harness and the newer column plug. Will have to move a few of the pin positions around in the plugs to make everything work. If the 77 is an auto, and yours a stick you will need to swap the clutch / brake pedal / steering column mount out of the newer cab along with the clutch master cylinder etc. into the 77 cab. Also your brake line fitting depending on your chassis year could be metric, the 77 will be SAE. You could uses the newer master cylinder, brake booster, or re flare your lines for the SAE flare nuts. As forementioned the Body mount bushings will need to be the 81 and up style. Hope this helps out. I am sure I missed something but that should cover most of it.
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I appreciate all the info guys, it gave me a lot of things to plan for..... With all of the info i have a few more questions:
1.Will a 2" or 3" body lift take care of the center section being different or will it still need to be modified?
2.The gas tank on the 1980's frame is on the same side as the 1977 body, my question is if i get a gas tank for a 82-86 frame, will the filler neck off of the 1977 work with that gas tank?
3.Because of the frame and body being different year models, would i use a sending unit for the frame year model or the body year model, or just match it with the gas tank?
4.If i use bumpers for the year model of the frame,that should take care of the mounting issues, but would it effect the different year model body in any way?
5.I have body mounts for the year model of the frame, will they work with a earlier style body?
That's all the questions i have for now, sorry there is so many, but i like to be prepared and its hard not to want to pick everyone's brain here..... Thanks guys.....
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(1) I know a 3" body lift will clear. Not sure on a 2" I would cut the floor over a body lift.
(2) The filler neck will work from the older tank. Right and left gas tanks are the same just mounted in the cradles from the opposite side. One note, the fuel tank cradles will fit from 73/80 to 81/87 etc., and visa versa. However the bolt holes are in a different spot on the frame. You will need to weld new nuts over the empty holes on the cradles to line up with the holes in the frame. Same is true if you buy brand new cradles, they don't have any nuts on them..
(3) I would stick with the sending unit to match the year wire harness you are using. I am sure the other years will work but might have a different plug?
(4) You can mix and match bumpers but i think the 73/80 bumpers look stupid on an 81 /87 truck, I also think the same about 81/87 bumpers on the 73/80 trucks. You are talking maybe a few hours to make the 73/80 bumper bracket so it works on the 81 and newer frames.
(5) Yes use the body mounts that go with the frame.
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Blazin, great info. I was just trying to figure out why my '79 brake lines (K10 chassis) won't thread into my '83 master cylinder? (C10 body swap). The hump was pretty easy and as stated. Used the '83 harness, evap emissions (charcoal can), '79 radiator on '83 support.
If anyone knows the thread sizes, '83 MC & '79 MC lines, I'd like to see of there's an adapter bushing available.
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Like I said in the other post about the lines. I would cut them, swap on metric nuts, and re flare them.
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Thanks!
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While your swapping the body over, grab the steering box from the 2wd and put in cross over steering!! You will be happy you did!