Thanks for all the information. I knew that K5s changed frames in 78 as I've worked on several of them in the past. I've just never done any extensive work on a suburban. Here's a picture of the last Blazer I have almost done.
The 77 is a 3/4 ton and the 88 is a 1/2 ton so 3/4 ton frame under a 1/2 ton body. 1/2 or 3/4 shouldn't make any difference. I think the transfer case shifter hole in the tunnel is even the same.
Just a quick question. Is a 1977 suburban frame the same as a 1988 suburban frame?
I'd like to put a 88 body on a 77 frame without a bunch of hassle. I do think the front frame horns are different for bumper mounting as the truck frames I know are. Is there anything else?