on both sets of windsor pi heads I have there are the letters pi under the casting # by the exh. ports. not sure of the romeo's
absolutely, always look for the PI stamp. As far as PI heads, never spend more than 100-150 on a set of low milage heads complete. Stay away from police vehicles or anything like that. In general, police, cab, or any other public vehicle have been either used extensively, or have been abused. Some, more than others, but I wouldnt risk it.
Get yourself a pair of good PI heads
www.car-parts.com is always what I recommend. Make a deal with a parts or salvage yard, bullshaz em, and have them send you the heads. Take them to a good machine shop, have them pressure test them for cracks, and if they test out, send them the cash.
The majority of society, especially with the mod motor used in so many vehicles, doesn't know or isn't aware of the value of PI heads to performance enthusiast as ourselfs. Be creative and you can save yourself a lot of dough. If you live close to a big town, chances are there are several sets of PI heads sitting close to you that will go for anywhere from $50-150 complete.