Swapping rear end question

Well, thanks to your guys' influence, I am going to swap my rear end rather than doing gears in my 7.25. A guy local has an 8.75 but is open and 2.76 gears and wants a fair amount for it. I found another guy with an 8.25 that he says is out of a 73 Duster. Wants a lot less for it. Unsure yet if it is sure grip or what gears. I plan to go with the 8.25.

That being said, I have a 72 Scamp. Is the 8.25 a direct fit or what all do I need to do? Is the driveshaft fine? Didn't the 73s come with BBP? But the perches and width are all the same? Just want to make sure I am covering my bases. Thanks all.