Inside Chrysler: 1955-56 police packages
I cannot make any claim to accuracy for the materials that I have used to make these articles (the journals go back 50 years). This is not an exact account of events, living persons, places or times.
The Poly-head 315 engine was in Dodge's first complete Police Package, in 1956. It was a first genuine fleet buyers’ effort for the company.
DeSoto and Plymouth had been famous for their fleet car performances for years, but they were “just” taxi cabs. Dodge aimed its new “Police Pursuit” at the State Police and larger Sheriff departments.
The model was available in two or four doors. It had heavy duty suspension components, including anti-sway bars at both ends, and reinforced body joints, braces, and seals. Large 11 inch DeSoto brakes were included, along with a little known brake lining called, "non-organic." That meant is was man-made stuff and not asbestos. The recommended transmission was the Powerflite, although a heavy duty Dodge truck clutch and three speed standard transmission could be fitted.
California is credited for its loyalty to Dodge, but it was the Missouri Highway Patrol which started with and remained loyal to Chrysler marque cars for patrol duties. In 1956, while California HP was still testing their 1956 Dodge Pursuits, Missouri HP had already put a fleet to work! Missouri had purchased ten Dodge cars for their first unmarked patrols in 1953. They bought more, due to their excellent speed, handling, and economy of operation, in 1954. In 1955, they also bought some Dodge units for marked patrol. In 1956, 80% of the Missouri HP fleet was Dodge, along with a mixed bid of a few Fords.
No records were kept of the purchase total of the 1956 Dodge Pursuits. Indiana changed their fleet to the 1956 Dodge. Missouri changed their fleet, and would keep MoPar right up until the end in 1989. California purchased 400 Dodge Pursuits along with 400 Pontiac Chieftains. Like most states, they tried to please everybody. The California experience with the Chieftains was mostly positive, but the Dodge blew the competition away. When the second buy came along in late spring of 1956, Dodge Pursuits in the California fleet had proven so outstanding that an additional 200 were purchased. Unlike the first batch, they had the 315 CI D-500 Hemi engines in them — the 8 barreled 315 CI Hemi head D-500 was available on the first Pursuit packages.
The brake system on Chrysler cars had been the Lockheed hydraulic units (actually designed by Carl Breer’s team, loosely based on Lockheed’s system) which were on the first Chrysler cars built in 1924. In 1956, Chrysler went to an across the board switch to a system of its own design (possibly still supplied by Lockheed). As usual, it was over engineered.
Each wheel had two brake cylinders. The center plane design allowed the brake lining backing to twist, putting the lining in full contact with the brake drum, increasing the brake sweep and power. When they were working, there was no more powerful brake system. However, they were a mechanic's nightmare due to their complexity and unforgiveness in adjustment. They had to be right to work right. (This system appears to have continued through 1962).
For all the complaints about drum brake design, they could be just as effective as any other brake system, had there been an engineering interest in making them better. Chrysler used a little known lining for its fleet cars, a sintered metallic material, just as is used today. A little known company became a supplier to Chrysler after its “Grey-Rock” brake linings not only out-stopped Chrysler’s, but refused to fade, at a torture test at the Chelsea Proving Ground.
The problem was that when the Grey-Rock linings were cold, they could be erratic and "grabby," causing a regular driver some anxiety, whereas, fleet drivers could be easily training to warm up the brakes first trip in the morning. Usually after that, no special attention would be needed. Trying to educate the general public in use of such a material did not seem feasible to Chrysler at that time.
The 1956 California Highway Patrol tests took the car through maximum acceleration up to 70 miles an hour, then panic punched the brakes, attempting a maximum braking situation. Without allowing for any cooling, the car would again be max accelerated back to 70. This was repeated four times in a row; after the fourth stop, the car was maximum accelerated to 90 miles an hour. Again, the brakes were punched in a panic manner. This was repeated. Then the car was taken up to wide open throttle, as fast as it could go, and the brakes were slammed on. This exercise was repeated four times. The only car to pass was the Dodge. The brakes were extremely hot, and had all sorts of funny smells, along with whiffs of smoke coming from them. But they absolutely refused to fade! The secret of the sintered metallic linings is that the hotter they got, the better they stopped!
In 1958, Chevrolet had to replace all the brake systems on police cars they had sold to head off a major lawsuit. The rear axle liked to separate from the car in a panic stop! (Where was Ralph Nader then?) The brakes were the same size on the 1958 Chevrolet as they had been on the 1950 model! From 70 miles an hour, you got maybe two stops, and no brakes, period! Replacement of the regular linings with metallic solved the problem.
In California, Dodge faced Pontiac, Buick, and Mercury in 1956. Mercury was disqualified because it failed the brake test miserably. Buick too had lousy brakes. Pontiac was a little better, going through the four stops from 70, but was not able to hold on at the first try from 90. After Dodge had whipped its competitors with its four high speed panic stops, an instructor took the Dodge on the high speed chase course. In the entire length, there are at least 10 places where maximum effort braking is required, bringing the car down from a high speed, over 80 mph to a much lower speed of around 20 to 30 mph. The instructor ran the Dodge through the course, without stopping 10 times in a row. The brakes never offered to fade, pulling the big Dodge down at a measured 25 feet per second, squared! Powerful, but confidence inspiring, brakes!
Plymouth was aided in their creation of police vehicles by the fact that Chrysler chassis components were usually interchangeable between divisions. Lee Petty proved that to be true when his relatively light Plymouth, bolstered by numerous Chrysler Imperial components, started whipping everything on the track.
This was particularly true for brakes; Chrysler brakes bolted right on to the Plymouth. In my 1958 Belvedere and again in my 1959 Sport Fury, I changed the brakes to the Chrysler sized drums, which were 12 inch by 2.5 inch hefty beauties. However, the Center Plane brakes were adopted across the board by all divsions in 1956. This did not mean that they had dual wheel cylinders as did the D-500 in the front, or the Police Pursuits which had them all the way around. The standard center plane brakes were single cylinder in normal production.
After downsizing in 1962 and going to a 10 inch brake drum, the 1963 Dodge and Plymouth Pursuit (116 inch and 119 inch wheelbase) used 11x3 inch Bendix drum brakes. The 880 also used the same sized brake drums, but the Chrysler 12x3 drums were available and interchangeable on all police pursuit models. They truly were not necessary on the smaller Plymouth or Dodge; the Dodge 880 and Chrysler Enforcer were amply braked by the same size drums.
Chrysler stuck with these brakes for too long; in 1960, the Valiant was introduced with the Bendix brake system, and in 1963, Chrysler adopted the Bendix brake system across all its car lines.
One magazine that tested the 300J took the big sedan through a series of torturous brake tests from high speeds. On the eighth near panic stop, the pedal finally faded to near the floor. After a brief cooldown, they started again. Stops of 32 feet from 30 miles an hour and 167 feet from 60 miles an hour were recorded. The brake drums were cast iron, 12 inches by 3 inches wide. They were heavily flanged on the rims, and deeply finned all the way around to radiate heat.
— Curtis Redgap