1993 Mustang Wheel Back Spacing Help

[93gtmustang]

I want to get 15x8 Weld or Summit Draglites for my slicks.
Should I go with 5.5 or 4.5 back spacing?
Also, whats the widest tire I can go with without modifications?
Thanks

 

[faststang90]

https://www.billetspecialties.com/cartview.asp go to down loads and theres a wheel fittment down load. u can get all the back spacing and size

 

[Hyland33]

im pretty sure i went the the 5.5" backspacing and i had 275/50's on my prostars and they rubbed the quads and i had to roll the fenders too..came really close to the exhaust too...i'd just go with 255's and play it safe