Tire Size

I have a stock 1999 Z71 Silverado Ext.Cab. Can I put 305 size tires on it without rubbing?

most likely the biggest you can go without a lift are 285's, bigger will rub.

They will barely, and I do mean Barely...fit. But they will rub on the front wir dam, so you will have to trim it a bit on each end.