I would go for a F150 5 on 5.5 rather than the F250 8 lug setup personally. Here are some specs for the F150. However, if you like the 8 lug setup... go with the 1978-1979 F250 Reverse Cut / High Pinion setup.
1966-1970 Reverse Cut / High Pinion Drum Open - King Pin 5-260x 2.75 x 1/2 Inches
1971-1972 Reverse Cut / High Pinion Drum Open - Ball Joints 5-260x 2.75 x 1/2 Inches
1973-1975 Reverse Cut / High Pinion Drum Open - Ball Joints 5-297x 2.75 x 1/2 Inches Panhard bar has a separate mount on the axle tube
1976-1977 Reverse Cut / High Pinion Disk Open - Ball Joints 5-297x 2.75 x 1/2 Inches Some 1977's had 2.75 x 3/8 Inch Tubes
1978-1979 Reverse Cut / High Pinion Disk Open - Ball Joints 5-297x 2.75 x 3/8 Inches Some had 2.75 x 1/4 Inch Tubes
F-150 Dana 44
8.5-Inch Ring Gear Diameter
1.31-Inch / 30-Spline Axle Shafts
1.38-Inch / 26-Spline Pinion
3.73 & Down / 3.92 & Up Carrier Break
Coil Spring / Radius Arm Setup (F-250's and 1977-1979 F-150 Super Cabs have leaf sprung Dana 44's)
5x5.5 Wheel Bolt Pattern on F-150's (F-250's are 8-lug)