What size are OEM wheels and tires for a '70 Ford F-250?

What size are OEM wheels and tires for a '70 Ford F-250?

Depends which model

The 1970 F-250 with a 6100 GVW came with 8.00 x 16.5 - 8 ply rated tubeless. Optional tires were 8.00 x 16.5 - 6 ply front and 8 ply rear tubeless.
The 6900 GVW came standard with 8.00 x 16.5 - 6 ply front tires and 8.00 x 16.5 - 10 ply rated rear tires.
The 7500 GVW truck came with 8.75 x 16.5 - 10 ply tubeless tires standard. The first option was for 7.50 x 16 - 6 ply fronts with 7.50 x 16 - 10 ply rear tube-type tires. The final option was for 9.50 x 16.5 - 8 ply rated tubeless tires.
Not my work, for more info:
For wheels check car-part.com