73 duster 275/60/15????

Hello guys,
I search the thread but can't find anyone with my particular scenario. I'm trying to figure out what I can fit for tire wheel combo on my 73 duster. I wanted to run a 15x10. With a 275/60/15. The leafs have been relocated in about 3". I guess my biggest concern is back spacing and if the 275/60 will clear. Thanks.