this has probably been asked a million times but i need to know in a hurry-i have a set of 26x10-15 MT slicks and i have a set of 15x7 rims layin around-will these fit on there? i had them on 15x8's before but im using those wheels for my radials now. any help

By the way the 15x7 inch wheels have 4 in backspacing and need to know if they are going to fit with the slicks on my '70 with stock rear and unrolled fender lips.