wheel help? need help on back space

[papa-bach-racing]

i have a 84 cutlass im looking for wheels and wondering what backspace i need i want to run 3.5 in front and 10 in in the rear

 

[93notch408]

i was looking online and seen 15x8 with 5.5 bs so ill fig a 10 inch rim would need 6.5 inch back space just like mustangs find a buddy with 15 by 10's on his fox with uni pattern and see if they fit...

 

[papa-bach-racing]

i herd on a 10 in wheel 4 bs ??? thats why i posted anyone els hve any input thanks for looking