SBC into 90 Fox. I want to convert rear 4 lug to 5 with posi. From what I've gathered the standard width is 59.25. Currie Ent. has a rear that is 59.50 . Ebay has an 8.8 empty rear assembly. Am I on the right track. speedway has a complete setup with posi, but it's 54". Can anyone lead me in the right direction. Thanks