8 1/4 F Body rear end fit in an a body?

Check the spring perch spacing and see if they are the same, pretty sure they are. Only thing left to check is the width from drum to drum. The Aspen is going to be wider. Will probably fit depending on what wheel/tire combo you are using. You will also need to get your drive shaft shortened because the 8-1/4 has a longer snout than the 7-1/4.

So to answer your question it will kind of sort of fit, but measure just to make sure. You can do that with the rear in the car.