will a 17x9 wheel with a 5 1/2 back spacing work on 1998 firebird.

 

TTT

 

Might be a little close to the outer edge of the fender, or even stick out past the edge. A stock WS6/SS 17x9 55mm offset has about a 7-1/8" backspace. You're moving the wheels out 1.5" more than those wheels. It only has about a 13mm offset, if my calculations are correct.

It would actually stick out of the fender about 1/2" farther than my 17x11's......

17x11