Hey That Car looks Familiar!
I think he has addressed the Rearend question.
I don't understand the trans.description.
The P-O-P says CY70,yet his description in it now is a CO69?
Also the Alternator should be a 837 37Amp,not a 796 61Amp as showing now.
And the Carb is dated 1972 & showing a Man trans.application,it should be a 4492 for Auto trans LS6, not 4557 as is now.
1968 dated SS rims also seem a little to early too.
Not trying to take anything away from this Chevelle,as I wouldn't mind owning a twin.
Nice!