Wheel backspace/offset

[CATMdude45]

I know there is a thread with folks showing off their rims/tires but very few people talk about what offset they have. My issue is the 1952 3100 I bought has a chevelle rear end installed and the tires that are on it are terrible, the rims were modified to fit the 5 bolt by 4.75 lugs. It has 14 x 7 in the front and 15 x 8 in the rear but the two rear rims do not even match. I am looking to get new wheels and tires. I am not a fan of low profile tires so I am going to stick with 15 or 16 inch rims. So here is my question.....what offset should I be ussing, I am thinking of sticking to the 235/75/15 tire.