That front tire is to short. Not sure what spec was on a firebird stock but on a Camaro it was around 25.5- 26" front and back. I would find a set of tires that will allow you to run 25.5-26" up front and 26-26.5 out back. That will keep your sidewalls pretty even and the 69's look better with a slightly larger tire out back to fill up the fender wells. Go to
www.tirerack.com and look at the specs for different tires. You kind of screwed yourself with that skinny front wheel. I'd go with a 225/50/17 and a 245/45/18. This will keep your sidewalls even and these tires are the correct widths for your rims.
http://www.tirerack.com/tires/Spec.j...1=yes&place=21