what backspacing will i need to fit a 275/40/17 on a 17x9 rim on a 72 chevelle (ok its a malibu)? and will i have any rubbing problems?

10" wheel = 5.5 BS
9" wheel = 5 BS
8" = 4.5 BS

Those tires will fit nicely.

Any where from 5 to 5.5 will work

Mark, what size are the rims and tires on your '70 they look nice.

Thanks, Dave!

295/50x15's on 15x10 rear
235/60/15 on 15x7 front