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Dodge Diplomat Cop Cars (Police and Squad Cars)

Police Car Information: (Courtesy of CopCar George Chang, Tom, Steve, Malcolm, Mike and Others)

Visible clues that an M-body was formerly a police car:

"S" In the VIN #: This indicates the heavy duty 4bbl 318. This almost always means "police package". A FEW private owners may have ordered that engine option, but they are almost exclusively seen on police cars. However, some municipalities did use police cars with other engine options, i.e. ordinary duty 4bbl 318s and even 2bbl 318s.

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 15x7" 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.

Under Hood Clues:

Look for an ID tag on the top of the left hand inner fender which is held in place by two screws. On the plate is all of the body, trim, paint color, style and manufacturing info. For model years prior to 1984, Chrysler, Dodge and Plymouth used the "A38" designation for police packages. From 1984 forward Chrysler changed the code to "AHB". The code should be in the second or third line of information. A38 was dropped after 1983, it was used on the Diplomat/Fury for the those models with the pursuit six cylinder.

49-state smog certification. If it comes with "California Smog Certification", it's a civilian car.

4 BBL Carburetor, 5 Core Radiator, Heavy duty transmission cooler in front of the radiator, power-steering cooler (finned fluid line), heavy duty alternator (noticeably larger than the civilian version), NO computer mounted on the air cleaner - it's under the dash board.

There may be heavy wires visible which have been cut/capped off

Other Visible Clues:

Other police car specifications not found in civilian M-bodies:

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. (Specs from Dodge, Plymouth & Chrysler Police Cars 1979-1994 and the Allpar website).

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. See the "Rear Ends/Gear Ratios" section (coming soon) titled "How To Identify a Sure-Grip Rear End". Civilian M-bodies 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 M-bodies have the lighter-duty axle tubes that narrow in diameter as they get close to the differential.


Good Model Years for Police Cars (Courtesy of Malcolm Adam, Norm and Mike)


First of all, realize that all Dips/GFs were a pretty similar run from 1980 right up to 1989. Pre-1980 models (starting in 1977 per Mike) had significantly different sheet metal, but still the same underpinnings. With that in mind, the best years for police Dips/GF's are:

1980 - This was the last year in which the newer body style and the 360 cube motor were offered. Don't get caught up in a nationwide search, because they were quite rare and it's just as easy to replace a later model year 318 with a 360.

1984 - Considered by some to be the best as they had the best performance, per those who drove them in actual duty.

1988 and 1989 - From 1988 on, the front K-frame was finally beefed up. Previous years tended to bend the upper towers inward, needing constant adjustments to the camber and toe. Eventually shims had to be installed to give more adjustment, as none was left.

Special note: Avoid 1985 models. Chrysler changed carburetor manufacturers and began using the "Quadrajet/Chevy" type carburetors. 1985s were known as the dog year cars.

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