larges tires front and rear 15" on 73 duster

I am looking to run 7" on front with 215-60-15 and 8" on back with 275-60-15.
Both sets have 4" back spacing. 1974 Duster.
I have run 15" police car wheels on this car years ago with 235-60-15 all the way around with no problems.

I would like to hear any feed back from the members on this subject also thanks.