68 nova rear wheel back space

[MonteMike79]

Didn't want to start a new post and thought this was close,

I have a '69 Nova and want to go to bias tires. Firestone 6.70/15 in the front, the rears I would like to have a bias but want to keep my tail pipes and don't want to raise the rear. Was looking at the Coker L78-15 with a 7" wheel. What do you guys think ? Also saw Camaro in Muscle Car review running the new MT sportsmans and looked at those, but would like a more vintage tire tread if I could. Also looked at the MH 275/60 but they say to use an 8" rim minimum. Would like to run the Pro Tracs but they say the same thing.

Thanks for any and all help/pictures.