4in vs 4.5in bolt circle rear axle

mikebee said
4.5 bolt pattern is definitely stronger,and it has the 1/2 studs too.also I've had a lot of small bolt 8.75s with the 489 case in them.

true.
my 70 340 Duster came with 4 inch bolt pattern 8.75 with 489 case delivered from factory that way. I suspect 71-72 was that way as well