87 to 78 bed

[hobbz]

I have an 87 and the bed is beyond repair. I have found a 78 bed in real good shape, and wondered what I will have to do to make it work.  Is the gas tank being on the wrong side the only issue? Are the body lines and mounts the same?

[81_Chevy]

body lines and mounts are the same. the only thing different is the tank that you would have to modify. the tailgate is also different, but you shouldnt have to worry about that.

[hobbz]

I would be getting the tailgate with the 78 bed. Thanks for the help.

[BSR63]

I have a 76 SWB fleet, and the bed was way beyond repair in terms of labor. I purchased another one, year unknown with dual square fuel doors instead of the exposed round fuel fillers. It fit with 100% no issues. I replaced my dual tanks cause it was cheap and I had to purchase all of the rubber hoses, etc.....
I have searched all I could and the only thing I can find are the fuel doors as being the only major change. Metal and lines are the same from 74-87. Will have changes with trim and possibly tailgates.
If you find out anything different let me know.

[BSR63]

I recently put on the bed that I found, year unknown/dual square fuel doors, and the body lines did not match up at all. They bed lines were about 1/2 inch high on both sides. Thought it may by the cab mounts being worn out, but the fenders lined up with the cab and the old bed was good to go.
The tail gate from the 76 was no way going to work. So be sure to consider the tail gate mechanicals. The newer bed had a one round and one oval tailgate pivot points, and the 76 had 2 round pivot points.

[Captkaos]

There is no difference in the 73-77 and 78-87(91) short beds other than the gas opening.  If it isn't lining up there is another issue.
For tailgates use the Tech article in the Tech section for a guide on how to proceed. 

[Greybeard]

If you are still interested ...the rear cab mounts are shot that's apparent, the quick fix is a 1/2" plate under the body mount with a 5/8" hole in the center. The front fenders will always remain in line with the cab because the entire setup is bolted together. The stock rear cab mounts are rubber and rot, get soft and droop. Maybe that's not your problem but it sounds to me like it is. If you pull a string from front to back the body lines should pretty much follow the line if the cab lines drop at the rear that it's the mounts are bad. However if the string line follows the bed lines and arrives at the front way above the headlights then the bed isn't mounted right somehow.

[BSR63]

Found out that the second bed I got was BONDO'd to the hilt. So much mud that I am on my third bed. But awesome info on the spacers. I am thinking about all new poly bushings when I get a chance. But thanks for the line info that will be used.