Getting the old filter off is not the problem, finding what ever Ford used to bond it to the pick up tube is the hard part. Maybe mikeo0o0o0 knows?
Was a used one the much cheaper than a new one?
Since your bed has been off before that's the easier route to go.
What "Ford field of dreams" are you talking about?
77&79 F250 Rich & Penny
77 351M auto, a/c, add a leaf 33x12.50's
78 (79 headlights) 460 4 spd, 4", a/c and 35's
79 351M 4spd 6" Skyjacker Edelbrock-Holley-Hedman 35's
99 Ranger 4x4, 98 Expedition 4x4, 73 Bronco Hillbilly-Bug
71 Bronco 302 35" Boggers 5.58 gears spool/locker