81-87 square body frames

[HotRodPC]

The frame may have had some slight changes, but none in the rear

Yep. That's what I'm saying. That hitch oughta fit from 73 to 87.

 

[Swims350]

width would be the only thing I could think of to effect what it fits but they should not have changed width since beds interchange.

Now the frames from 73-80 were alot heavier built and such compared to the 81-87's they have lighter crossmembers and such.

As far as botl holes not lining up that's what they make drill bits for.

 

[davbell22602]

Well since the frames are the same in the rear. Then the person told me this bad info must be a idiot and not know what he's talking about.

 

[Old77]

...always completely possible

 

[HotRodPC]

Well, he was correct. It will fit an 81-87. It'll just fit more than that.

 

[davbell22602]

Well he trying to get across that there was 2 different frame styles in the 81-87 pickup eras when mounting a hitch.

 

[HotRodPC]

I'm not aware of it, but it he is experienced in installing hitches, maybe he knows something we don't. I just know there is a differance on the front bumper the way it mounts to the frame from an 73-80 to 81-87. That was the only differance I was aware of. Also I know if you are interchanging frames, like a 81 frame to a 73 body, or more common, the 81-87 body to to the 73-80 frame, then you use the mount that go with the frame, so that does tell me, there must be a differance in the body mounts too.

 

[89Suburban]

I swapped a '78 C-15 Burban body onto a a '85 K1500 Burban frame and the mounts lined right up, even the frame harness plug matched on the firewall. Just had to hump the floor over the transfer case. Like Swims said, if it's different at where the actual reciever bolts on, that's what ya got drill bits and shims for. I can't see the frame or rail face widths being different...

 

[HotRodPC]

Just had to hump the floor

You know where this is going !!!!

 

[Old77]

Not when he just came back after a 3 day hiatus!!!

 

[89Suburban]

Doh.

 

[nvrenuf]

When I was trying to sell someone said there was change in frames in 81-83 and 84-87.

Iirc, this is correct w/ respect to a K5. I'll agree with everyone that the basic changes are 73-80 and then 81-87(91) with the obvious changes being the front frame horns. While researching what frame would fit my 91 body (original frame was bent) I found that in the mid 80's there was a change in the K5 floors that caused a change in the shape of the middle of the frame. GM lowered the rear passenger floors for improved comfort, early frames had a "rise" in that area that interferes with the body so there is a part # change in the early mid 80's. The width is always the same. For the sake of things like hitches and bumpers it's the basic 73-80 and 81-87(91) groups.

 

[Old77]

Nice info!!! I had no idea about this! I wonder if any of these changes would affect the holes where a frame mounted hitch would mount too??

 

[HotRodPC]

Iirc, this is correct w/ respect to a K5. I'll agree with everyone that the basic changes are 73-80 and then 81-87(91) with the obvious changes being the front frame horns. While researching what frame would fit my 91 body (original frame was bent) I found that in the mid 80's there was a change in the K5 floors that caused a change in the shape of the middle of the frame. GM lowered the rear passenger floors for improved comfort, early frames had a "rise" in that area that interferes with the body so there is a part # change in the early mid 80's. The width is always the same. For the sake of things like hitches and bumpers it's the basic 73-80 and 81-87(91) groups.

Cool info. So what year was this change in the Blazer? That will sure be something I keep in mind when looking for one. 84 and later???

 

[HotRodPC]

Nice info!!! I had no idea about this! I wonder if any of these changes would affect the holes where a frame mounted hitch would mount too??

No, it won't the affect the rear bumper mount or hitch mount at all. Or the front bumper for that matter.