1971 4x4

[Bowtie7ty]

Hey this is the first time ive posted anything on here but ive been a member for a while. Im 16 and me and my brother just started on our 4x4. We got it for a pretty good price for what it is. Started off as a 71 2wd and it was put on a 4wd frame. I took the bed off the other day and started blastin it when i found that it was cut maybe 8 inches behind the cab. Its two clean cuts on each side and somebody tried to weld it so where u couldnt notice. I have no idea what would make them do this but i was wondering how bad it was. The only thing i can think of is i think that 80s chasis were longer than 67-72s but i still dont see why they would cut it behind the cab to shorten it instead of the back of the frame. Should i box the frame to make it stronger just incase? Any advice would help. Thanks