BGN rear end question

I'm currrently building an 85 regal stock car and had a question about the rear end.
The stock metric rear end has a 4 3/4 bolt pattern and tiny drum brakes. I've heard that the GN has a 5 inch bolt pattern and larger brakes. I was wondering if this is true or not.
I haven't been able to confirm this and all I 've heard was hearsay. So I figured on asking you guys. Any help would be appreciated. Thanks guys.

im not shure about the 85 GN but i know the 86'-87' GN had a beefed up 12 bolt with bigger brakes (alot of people run in the 10' and some in the high 9' with the stock rear end. but rember that not all GN rear ends where posi. the quickest way to tell if it is a posi or or not is the posi has cast iron brake drums and the non posi has aluimum (i know i can't spell.)

GN's did NOT have a 12 bolt. True, not all had the G80 (posi) but they were 8.5 instead of the smaller 7.5. No, the bolt pattern is not 5 on 5 but 4 3/4, just like most GM cars, and some did come with aluminun drums and posi. GNX! Best way to tell is to pull the cover.

Thanks for the correction GN1220. I ment to say 10 bolt but i messed up. (can't type for s%$#)