can an aftermarket v6 exhaust be used in a v8 car?

v6 mustang with aftermarket exhaust (i think ive heard the stock ones only have one exhaust tip, whiule this one has 2, and it looks pretty wide). say i were to, idk, throw a v8 in there eventually, would i be able toi use the same exhaust? i have no clue which on it is, though it says flowmaster on the tips, and the pipes go to both headers through i think an x-pipe? not very informed on this subject