what size car tires can i put on my 1950 ford 8n with oem rims in thefront?
Take the rims to your local tire shop and they will measure the width of the bead of the rim, and the height of the original tire and will be able to install a tire that is compatable.
If I remember from the one I had 40 some years ago they were 6.70 x15 which is the obsolete numbers but maybe that will give you a lead to what you need. Your best choice is to DAGS for Ford tractor clubs in your area. There are many antique tractor clubs in the US.
you can buy a new one for 15 bucks.