Imperial: Y body or C body or D body?
In 1967, Imperial finally moved from body-and-frame to unit-body construction, sharing its chassis with Chrysler’s unit-bodies; its small production had not merited the investment in unit-body construction, given the life of the tools and dies. Some believe the Imperial was a Y body during its unit-body years, but evidence suggests that it was never officially a Y-body until the 1981 series.
John Capron described the newer 1981-83 Imperial as being “a Y body, even though it obviously had a great deal in common with the J body [Mirada/Cordoba]... we doubted that the car would be successful and that inevitably led to the unofficial ‘Why’ car designation.” (Its main difference from the Chrysler Cordoba and Dodge Mirada was not exotic features or engines, but the instrument panel and electronic fuel injection, the first to be used since the disastrous 1958 DeSoto Electrojector. This did not work well, either.)
Daniel Bode wrote, “I am convinced that 1967 and later Imperials are C-bodies — they were [based on] Chryslers. This especially applies to Imperials built from 1969 until 1975. This position is also backed by Galen Govier who states in his books that 1966 and older Imperials were D-bodies whereas 1967 - 1975 Imperials were C-bodies.”
Daniel Bode wrote:
... the Imperial sub frame is different from that of a Chrysler. Not only is it longer, but the upper control arm mounting is different, the frame is mounted in rubber bushings, etc. The driveshaft has double U-joints on each end to eliminate the need for aligning the driveshaft, a feature not found in any other Chrysler. I think this was true until 1975, when the Imperial became the New Yorker Brougham. So now why should 1974 Imperials suddenly become C-bodies?
On the other hand: If you strip a 1969 - 1971 Imperial of its entire front clip and rear bumper, remove the interior and remove the backlight, you will no longer be able to distinguish it from a Chrysler, apart from minor details such as the vinyl roof material grain or chrome side trim. The 1969 - 1973 Imperials were always assembled on the same line than Chryslers at the Jefferson Avenue plant.
Imperials were treated as a brand of their own (it didn’t help sales at all, marketing them as top-of-the-line Chryslers in 1971 and 1972), just like the big Dodges and the Plymouth Furys and the Chryslers which were all considered individual makes. The 1969 and 1970 Dodge Monacos even had a sales brochure each of their own to set them further apart from the Polaras, yet exterior differences between a 1969 Polara and a 1969 Monaco are minimal. All these cars, except the Imperial, are commonly referred to as C-bodies without any dissent, at least in the years 1969 - 1973. So the mere fact that an individual sales brochure existed or did not has nothing to do with the body designation in question.
The “Y” in the VIN was used instead of the “I” for “Imperial” because the letter I could have easily been confused with a number 1. This is also true for the engine code appearing in the VIN, which never supported the letter I, and there was never a Chrysler 300I. So the Y just refers to Imperial as P refers to Plymouth Fury in the VIN and the Mopar car line designation. It has nothing to do with body designation.
I am still convinced that the entire situation is best described by calling 1966 and earlier Imperials D-bodies and 1967 and later Imperials C-bodies. I rest my case.
Bill Watson seemed to agree:
The 1967-75 Imperials were, indeed, C bodies. The confusion seems to come from people reading the 1966-67 Chrysler Imperial service manuals where they read about the 'C' Chryslers and the 'Y' Imperials. But they miss the bit where it says Chrysler C car line and Imperial Y car line. There is nothing about car BODY anywhere in the book.
Chrysler only mentioned car lines until 1972. On page INF-7 of the 1972 Passenger Car Parts Catalogue there is a listing of all the makes and such, grouped by body for the first time — A, B, E, and C.
Under C body there are four car lines: Plymouth full-size (Fury), Dodge full-size (Polara/Monaco), Chrysler, and Imperial.
In 1981, Chrysler used a digit for the car make (2nd digit), plus a digit for the car body (5th digit). The 1981 Service Manual lists for the rear wheel drive car body models -
J - Mirada / Cordoba
M - Caravelle / Diplomat / LeBaron
R - Gran Fury / St.Regis / Newport-New Yorker
Y - Imperial
Further in the book the is a list of car lines with the car bodies:
J - Mirada - X / Cordoba - S
M - Caravelle -B / Diplomat - G / LeBaron - F
R - Gran Fury - J / St. Regis - E / Newport-New Yorker - T
Y - Imperial - Y
Thus the 1981-1983 Imperial is still the Y car line, but now it officially has a Y car body. Strangely, Chrysler reverted to car line for the 5th digit in 1982, but went back to car body again in 1987.
The 1990-93 Imperial was again built on the Y body, but by then Chrysler no longer used a letter for car lines. Instead, Chrysler used car make and car body combined. The Fifth Avenue also used the Y body, and the only way to tell a Fifth Avenue from an Imperial by the VIN was the 6th digit - the series. The Imperial had a higher number than the Fifth Avenue.
The final word
Gil Cunningham of the Chrysler 300 Club wrote:
As a Chrysler engineer (1963-1982) I received copies of the Engineering Model Charts every month or so. These were products of Dept. 2120, Engineering Programing, and included a nice readable chart of body designations, car lines, plant line-up, engine availability, etc. There are three areas I would like to note:
1979 Cordoba/Magnum. In an example of “Body Engineering” (vs “Nameplate Engineering!”) these models became R bodies for 1979 even though they were carryover vehicles for the most part. The first 1979 Engineering Model Chart that I have is dated December 16, 1976 and lists the X (Charger/Magnum) and the S (Cordoba) carlines as R bodies. There never were any B bodies designated for the 1979 model year.
1981-83 Imperial. This car was always a J body, the same as the Cordoba and Mirada. The car line was Y, the same as years back. As far back as October 5, 1978 the Y carline is included in the J body area of the Model Chart. The name Imperial was added sometime between January 25 and September 10, 1980.
"D" Bodies. The earliest of these charts I have that specifically use the "D" body nomenclature is "V" Series, or 1964 MY. 1962 does not use it and I never located a 1963 Chart so can't say about that. The "D" body designation is used up to "C" Series (1967) when the Imperial is listed as a "C" Body.