I did a search and really didn't come up with any answers. I have a 90 Firebird Bandit II and I have always hated the factory wheels. I was looking into putting the Year One snowflake wheels that they put on the Burt Renolds TA's they built. That way It is still a factory style wheel that I can put a beefier looking tire on. My question is what it the biggest size I can go with out rubbing or any mods on a stock car? I was wanting to go a 18x10 but will that work in the front as well? Or will I need to do 17x9's all around? And what back spacing?

there is a lot of info on tires - use the search button.
without using spacers you can get 10's in the back and maybe 10's in the front if you file the end of the tie rod, or so i am told.
i went 255/60 15 on stock rims in the front and 275/60 15 on the rear on stock rims.
you can go a lot bigger than that with a 10 inch rim. but you may have rubbing problems in the front and rear.
use search - there are plenty of people that have done it before and they have some great ideas.

As I said I did do a search with no luck. Everything I found was either lowered or fenders roller or something. I just want to find out what the best sizes that I can go on a completley stock car.