How wide is the factory 10 or 12 bolt on a 69 Camaro?

[DFRESH]

Here's why--a buddy of mine has a brand new fabricated 9 inch housing with brace and all--work of art---looks better than what is under my race car---it's 54 in ---for the life of me I can't remember what a stocker is---he paid like 1200 for the housing--fire sale--400 bucks---like i've said--I never get exactly what I want, it's always whatever the best deal is.

Many thanks for whomever can tell me----

Doug