Tire size
 

What tire size can I put on the rear of my 70 Monte without rubbing with a 15-8.5” with 3 7/8” backspace? Picked up 2 beautiful torque thrust t70. Thanks. Jeff

My experience with those 8.5 shallow backset wheels, is, they don't fit under an A body with much of anything other than a stock tire. The wheel, itself, is nearly plumb with the fender as it is. I sold mine and bought 15X8 with ~4.5 backset and ran 275/60 under my '66, which has a smaller wheel house than the '68-72 Chevelle, Monte's.
Of course, other's may have different results, they usually do...