Here's what I read about it George.
Other Police Car Specifications Not Found In Civilian Models:
Engine: The engine should be a 318 with 360 heads, four barrel intake manifold, heavy duty exhaust manifolds, double roller timing chain, hyperutectic pistons, special piston-to-block clearances (allowable by use of the hyperutectic pistons), heavy duty chrome plated oil rings, forged steel connecting rods, heavy duty valve springs, high strength rocker arms, high temp cylinder head cover gaskets, high temp valve seals and shields, lubrite treated camshaft (4bbl hydraulic version had 430/444 lift with 268/276 duration, roller version had 391/391 lift with 240/240 duration), nimonic exhaust valves, special kolene cleaned cylinder heads, special silichrome-1 temp steel intake valves, and a heavy duty water pump.
Transmission: Transmissions will range from the heavy duty A727 (definitely available in 1983 and probably later as a special order), the 5-clutch A998 or the A999 (based on the A904). Some police cars may have 1st gear locked out (i.e. no manual downshifting to first gear – only automatic downshifting). This was done by Chrysler to prevent police personnel from slamming down into first to slow down quickly after a high speed chase and to prevent them from doing the same for quicker acceleration thus over-revving the engine. The lock-out may have been removed when the car was prepped for sale to the civilian market.
Suspension: Police cars came with stiffer suspensions and heavier sway bars than civilian versions. Some police cars may also have solid cast iron K-member isolators rather than the civilian rubber ones. This makes the ride somewhat harsher than their civilian counterparts, but greatly improves handling.
Differential: Police cars have the 8-1/4″ differential with Sure-Grip, and should also have the 2.94 gears unless otherwise ordered or changed. Civilian models have the 7-1/4″ rear ends without Sure-grip and much lower gear ratios.
Rear Axles: Police cars have single-diameter axle tubes. Civilian models have the lighter-duty axle tubes that narrow in diameter as they get close to the differential.
Tires: If they haven’t been switched, police cars will have wider performance tires. They usually came with Goodyear F32 P215/70 R15 tires.
Wheels: Police cars have 6 slotted 15×7″ steel wheels with 4.5″ bolt circles. Hub caps will usually be the small “dog dish” type that snap onto the center of the wheels.
Brakes: The brakes will have 11″ drums. Civilian versions) are 10″. The only exception to this are taxi packages, which will also have 11″ drums.
