I would suggest calling one of your local tire dealers like Direct or Discount Tire Co. and they will be able to tell you what is recommended for that vehicle.
back in 1979 the factory tire size was p235 75/R15
The original factory recommended tire size should be listed on a sticker in the drivers door jamb area.
Six cyl or 8 cyl
LT225/75R15
6x8
its on the vin plate on your door
BCI group size 56
Check your underhood emission sticker, it will have the engine size.
It's a 20 in. wiper blade
my 1997 e 150 has a 35 gal tank.
The Ford E-150 is a full size van ( 1/2 ton )
Anyplace that sells batteries can tell you the correct size you need.
1/2 inch. that's it!
Mine appear original or close and are 8.75 R 16.5 LT