60-62 and 63-66 bed difference

[62 bigwindow]

I have been looking for a fleetside short bed for a 66 GMC I have and found a guy local that has one from a 60 or 61 and curious what if any difference there is. Since the 60-62 suspension is different then the 63-66 wasnt sure if there was any difference in bed mounting. Arent the earlier frames slightly wider?????

[VonDog]

Yes the frame is wider - if I remember right the last sill ( by the tailgate) will need the mounting plates to be removed and re welded for the 66 dimensions. Also, the second to the last will just need to be re drilled. All else should line up.

[Clyde65]

IIRC the frame width at rear is 60-62=42" and 63-66=34"

[firemanjimtfd]

Here is the difference. The 60 62 rear mounting holes are wider on 60-62 beds . Here is my early bed on my 66 truck. You can either change rear cross member or cut mounting flange and move in. I have even thought of laying a piece of angle iron across and using all 4 bolt holes. Remember if ordering pre drilled wood which year bed because of different bolt location.