Hi John!
More or less it's the same thing. The internals, heads and cams, intake manifold and other bits are the same. There is one difference, however. The oil filter adapter. The POCV's used a different piece to accomodate an oil cooler. What I don't know is if this pertained to all, or just specific years. I have one of these oil cooler adaptors here. Unfortunatey, it won't work on a bird without being REALLY creative - and there's just not enough room for that. Is there a specific year you might be asking about? The POCV's engines made the change to the newer PI status in..... '98 or '99. I'll have to double check that though. I don't remember if it was the same as the Stangs or not.
Since we're discussing it - the POCV's had a better cooling system, bigger rear anti-sway bar and no top speed limiter, among other things. Contrary to popular myth, the stealth Vic's (you all know them, the blue ones) never used a 4V 4.6. It wasn't deemed necessary, or worthy, of Police use.
Keep in mind the Vic's had their airbox/filter on the driver's side of the engine, as opposed to the passenger side in the Birds. Yup, LX's too.