Rearend swap question

Sorry if this has been answered, I used the search and had no luck.

I have a chance at 8.25 rearend out of a 72 van will this fit under my 72 valiant? currently i have 7.25 with a 318 v8.

I may be able to snag 8.75 out of a similar year van at the yard but not sure if I want to do this unless it will fit under the car with out narrowing it.

I dont need spring perch's as Ill be having the valiant 4 linked

Thanks in advance.

B