try spacers first to see if they look good that far out, easier and cheaper first off than getting a widened diff. I got a falcon xp diff that is right length for saab 15inch chasers on rear but couldnt be bothered fitting it and getting a tail shaft made up. they are 4 stud 4 x 114 same as datsun. its a 3.9 ratio from memory with a 7.5 inch ceter im sure too, been sitting there covered for 12 months now. was going in coupe but sold that for the sedan.