Hey yall, I'm pretty new at this so please bear with me. But what year models stepside bed will fit onto a 1961 F100 frame? (my truck is not a unibody just to rule that question out) Will a 1963's bed work? thanks for yalls help.

 

Welcome to FTE

Don't know diddly about stepside beds, as they were only installed on Chevrolet/GMC

Depending on the wheelbase, there are two different lengths (6 1/2' & 8') of Flareside beds.

Wheelbase stamped on the 2nd line-far left of the Warranty Plate, riveted to the inside of the glove box door (1961/62); riveted to the left door face below the latch (1963/66).

 

For six foot and a half beds very late 1950 to 1979 is the same design. Late 50, 1951 and 1952 use the earlier fender design so you will have to drill mounting holes for the later.....53 up fenders on a F-1 bed.
Avoid the 48- early 1950 F-1 bed as it's a different design. 1953 to 1979 F-100 use the same fenders and from 1957 to 79, the same step or mini running board.

I have seen a few tall 61/2 foot beds in the 61-79 era. These have a little brace over the fender like a 8' bed. These may have been long beds shortened but I have seen several short-tall beds through the years so I think it was an option.

Sometimes you can find a good bed and tailgate from a truck that has been converted to a trailer. If the sides of your bed are good it can easily be rebuilt as nearly every piece is reproduced. Also the sheet metal work is simple so panels are easily made as well.