Rims for Nova

Hay guys its been a long time since i've posted but I havent touched my car in about a year!!. I'm workin on it again but having trouble with correct rim sizeing. I want to know if I can put on some American Racing Torque Thrust 8" rims on the rear of my car? ( 17x8 to be exact) A lot of shops are sayin I can only go up to a 7" rim. Is this true?? What is the offset I need??. What is my bolt pattern. (5x4 1/2?). Lastly, how wide of a tire can I fit back there with the lip rolled??. Thanks guys, This rim issue is getting me upset. Hope someone can help Im really lost.

The bolt circle is 5x4 3/4
If you move the shocks in you can put an 8 inch wheel on the car.
I had a 1974 nova with 8 inch rallys on it.

What would happen if I mount a 8" rim on the car with out moving the shocks in. Will it rub or just not fit? What if the rim had the right off set. Will that work?