Yeah. It'll bolt in but the spring perches are like 1/2" wider apart, so you have to push the leaf springs apart a little. It'll fit, but it's not "right".
And the locator holes in the perches are HUGE (due to the goofy iso-clamp mounting) and don't properly locate the perches on the A body springs. To properly mount it, you'd need to cut off the F body perches and weld on some standard perches in the correct locations.
If you still want to undertake it, make sure it's not a 7.25 rear, not worth the effort. You can get actual A body 7.25s for a song. Or at least hum a few bars...
I’m running an F-Body 8.25 in my Duster with the correct perches and width. Works well for my purpose as it is a close match in width to a 67ish B-Body 8.75 and allows me to run a ‘97 Mustang 17x8 wheel. It needed longer wheel studs and the center bore isn’t right but all in all it worked very well.