there has been a recent discussion on V6power.net about the police issued FORD TAURUS, it had 160 HP compared to the 145HP in the mustang.
The difference between the Police heads and the stock heads were in the combustion chamber. The Police heads had an open, more unshrouded D shaped chamber, the stock 3.8's did not, they have the kidney shaped ones we are all use to. You can also find this head on the 95 Windstars btw... casting number F15E or F35E.