64 bonneville tires
 

looking to buy tires bfg radial t/as whats the biggest size i can use with 14 inch 8 lug wheels thanks

When I had 8 lugs the best 14" tire I could find was the 225/70-14 Firestone Firehawk 500.

Anything wider than 225/70-R14 that is available today won't be tall enough. Actually, a 225/70 is a little short as well but it will work; the closest modern tire to what was used on these cars originally is a 225/75-R14. The Cooper Trendsetter is available in this size, along with possibly one or two other brands.

I just found out today that Cooper stopped making 225-75R14 tires a month ago. I had to get a set of Mastercrafts, which are made by Cooper, but are all season. My tire supplier doesn't know how long those will be available, but he doesn't think that it will be long.