You're positive it's not laying in the bottom of the door?
Junkyard is probably your best bet, or someone around here with a parts truck.
81 F150 Flareside, Edelbrock Pro Flow4 FI, hydraulic roller 351W, E4OD, 4x4, BW1356
92 F150 RCLB 351W E40D BW1356 mostly stock