frame swap
 

I have a 1969 gmc 3/4 ton lwb with coil spring trailing arm setup. I would like to swap the truck over to a newer style frame with leaf springs and disc brakes. I know I could drop the body on a 71 or 72 frame, but I was thinking about using a 73-87 frame. Is this do-able? The 73-87 would be easier to find (at least in these parts) and probably easier to find the tranny and gear ratio I want. Any help greatly appreciated.

oh wow so many people loosing the coils now. you know I was talking to a guy the other day about the same thing. I got a 72 and was thinking of putting the body on the frame from the 79 parts truck just for the reason of the leaf springs and parts and such being newer.thats basically what your talking about doing same frame and same body style. another guy in the room said that the from assembly wheels and such would fit from wheel to wheel crossmember and all. as for the rest he thought they were different. Im not positive on it because I havent measured anything and all that. I thought about taking the tape measure (since both trucks are still assembled) and measuring were the bolt holes are on each one as to the other one.the worse that'll happen is I waste a little time and get a little dirty crawling around under it. (guess I could teach the kids how to measure it and ask them if they wanna help dad lol). anyway easiest thing to do would be measure it and see. if not then you can always take the leafs off and mount them to the old frame as well as the other stuff then your getting the new parts on the old truck and youll always be able to order the newer parts until the next upgrade because all your holes and such will be there. if all else fails you can look at it like I do. I got a cutting torch and welder that says it'll fit. if that dont work........ hmmmmmmmm theres always duct tape lol.

anything will fit with a torch and a welder

lmao that theories never failed me yet hahaha

The 73 up have a longer wheel base(4 1/2" I beleive). The later crossmember can be bolted under the 69 frame complete to give you the disc brakes. As far as the rear coil set up, it was really a good design, & the later rear diffs can be swapped in with a little welding.......trannys are also swapable. You can swap the body to a later frame, but you will be shortening the frame, & setting up cab mounts,& nodoubt redrilling holes to mount the box. I have mid 70's 1/2 ton parts under my longhorn,but still have the same chassis. good luck.....AL;)

I have a 72 3/4 ton GMC Camper Special frame here with leaf springs.. It is in Olympia, Washington... Just a little south of you... It would be a heck of a lot easier to install your body on this fram rather than trying to convert to 73 and later. Let me know.. wehepp@attbi.com WES www.ClassicHeartbeat.com

The Frame would work because the 73 - 87 frame is the same width as the 67 - 72 frame but there is one spot that will be a problem.. Look under your truck and you will notice the area where your cab sits, is Flat, the 73 - 87 frames coming from rear wheels to front wheels, the frame dips down underneath rear of Cab, so you would have to do a lot of modifications to your cab in order for it to work. Or you can always Lift the Front (Core Support and Fenders), then use a Body Lift Kit for the front Cab Mounts and Lift the Bed, but then are you wanting it to stay 2WD or do you want 4WD ?? Lifting would make it look like a 4WD and in my opinion, 2wd trucks that are lifted look horrible!!

I was thinking of doing the same swap for my 68 to make it a SWB but then after seeing how it would look, I just decided I am going to Cut My Current Frame and finding a bed..

Why would you want to get rid of the coil sprung rear end ? You get much better traction and a better ride with the coils than you do with leaf springs. The leafs arent more "modern" . Its just cheaper to manufacture leaf spring rear suspensions than coil spring suspensions.