1998s weren't called "Police Interceptors". The Police Interceptor officially became the trim name for the P71 starting in 1999. If your 98 has a "POLICE INTERCEPTOR" emblem on the back, someone added it. In addition, the center caps in your photo were not used on the P71 until the 2000 Model year. Prior to the 2000 model year, the P71s used the same plastic center caps as the Explorer. The 2000-2002 model year P71s used the Type 170 stainless steel center caps used on the Ranger. In 2003, Ford re-designed the chassis and went to new wheels, resulting in the use of different center caps (if I recall correctly). Ford is now using 17" steel wheels on the late model P71s. FYI, the 2003-up Panthers can use take-off S197 wheels, and use the same 235/55R17 tire size.
I can't tell from your pics, but the 98 P71 never came with a black grille. They used chrome grilles (same as the 98-up civilian grilles). In 99, they used a glossy black painted slat grille while in 00 they went to a matte black slat grille. In 2001-present, they switched to a honeycombed black grille with a larger Ford oval. I suspect in 2008 or 2009, Ford will switch to a tri-bar design similar to what they are using on most 2008-up Fords (reference the 2008 Taurus, Focus, etc...)
The 1998 P71 has a matte black rear fascia with chrome trim, while 1999-up have a glossy black rear fascia with blacked out trim.
The 1998-2000 P71/P72/P73/P74 all have the same NPI 4.6L 2V V8 as the 96-98 Mustang GT, while the 2001-up Crown Vics have the PI 4.6L 2V V8 (same as 01-04 GT).
Only the 1999-early 2001, and 2006-up CVPIs had 3.55s (optional 3.55s for 2006-up). NONE OF THE P71s ever came with Traction-Lok differentials as a stock feature. They are $87 options.
All 98-up Crown Vics have the same trans oil and power steering fluid coolers, while the P71s have an added engine oil cooler that is notorious for leaking engine oil out of the seals and hoses. The radiators are all the same, and the transmissions are all the same.
The P71s w/ 3.27s have speed limiters set at 130 mph, while the 06-up w/ 3.55s are limited to 120 mph. The 99-early 01 CVPIs with 3.55s had a special aluminum metal matrix composite driveshaft that allowed them to safely drive at 130 mph. Ford switched to regular aluminum for the 06-up 3.55 equipped CVPIs, so back it went to 120 mph.
Other than 99-early 01 and 06-present, the CVPIs all came with 3.27:1 rear axle ratios.
The 2000 model year had inferior programming, resulting in a meager 160 rwhp bone stock (less than 190 fwhp) whereas the 98-99s dyno'd at 180+ rwhp, right at the advertised 215 fwhp rating.
The CVPI's dual exhaust is the SAME as the dual exhaust on the Handling and Performance Package (HPP) civilian Panthers and the LX Sport civilian Panthers, with the exception that the CVPIs do not have the resonators at the tips. These resonators are only found on civilian models, and are not restrictive at all.
The civilian Vics that are not LX Sports or HPPs have a single exhaust with 2.73s in the back. All Panthers come with open differentials unless it was ordered with an optional Traction-Lok (P71 only).
The fastest accelerating CVPIs were the 99s and early 01s due to good factory programming and the 3.55 rear axle ratio. The 99s were the first P71s to get the 11.25" torque converter (same one used in the 4R70Ws for the Mustang GTs and Mark VIIIs). In 2003-present, all the Panthers gained extra weight and did not receive much more horsepower. In 2004, the Panthers finally got extra hp but only for the CVPI due to the new airbox and MAF (250 hp from 239 hp). Since the race-ready weight is generally around 4300 lb, 250 hp does jack schitt to make it competitive with the Dodge Hemi Charger (R/T and 5.7 Police Package) which weighs about the same, and has 340-350 hp.
