Will an 8 3/4 from a 69 belvedere fit an a body?

1970Duster said
To fit in an A body, all you need to do is move the spring perches in 1/2" each and use the corrected backspaced wheel on them and that it.

And others have suggested that while you're at it, you might consider moving the spring perches in to make a little more tire room under there.