Forgeline rear wheel back spacing is off help

[windycitychev]

I need help guys I purchase Forgeline GZ3 wheel 18x8 up front and 18x10 rear for my 68 chevelle SS and after mounting the wheels and all the rear wheels stick out more then I wanted and I'm not happy. I still have another 2-3 inches of room to be more tucked in. My question is what can I do to fix the problem 1) can the hubs be cut or can the wheels center hub be moved back some more please help