1978 Pontiac Grand Prix
The Grand Prix line started as a performance package for the Catalina coupe, which rode on the full-size B-body GM platform. It was distinguished by a unique grille and taillights, bucket seats, center console transmission shifter, and more. John De Loren was head of Pontiac’s Advanced Engineering, and tried to infuse performance into the entire Pontiac line. To that end he even OK’d the “Super Duty” 421ci performance package into a few Grand Prix’s for racing purposes. The clean 1963-1964 models featured smooth, unique hardtops that featured curved rear windows, and expanded on their performance engine options while adhering to luxury offerings for the interior. 1965-66 models continued with GM’s all-new boxed-perimeter B-body frame and shared sheetmetal, as well as continuing the unique stacked headlights, split grille, and performance/luxury image. 1967 saw the addition of the one-year-only Grand Prix convertible, and featured revised sheetmetal featuring hidden headlights with vents in the leading edges of the fenders for parking lights. 1968 saw a more baroque body restyle with a wide grille continuing with hidden headlights and a more formal top. 1969 was the introduction of the new corporate “G-body” which featured dramatically longer front ends ahead of the cowl. The new Grand Prix would have this exclusively for a single year before sharing it with the Chevy Monte Carlo. With a unique upright grille and headlights surrounded by body-color sheetmetal, it made for a dramatic personal luxury car, and sales shot up to over 112,000 units. Though sales slipped in 1970 and 1971, they rose past 90,000 cars in this version’s last year of production in 1972. For 1973 the third-gen based on the new “Colonnade” coupe abandoned the hardtop styling Grand Prix’s were known for to instead embrace the new coupe body adapted for pending federal roll-over safety standards. In spite of competition within Pontiac like the Grand Am, and outside with the Monte Carlo, Grand Prix sales were over 150,000 in 1973. Corporate Average Fuel Economy standards and safety regulations were changing the automotive environment, and the Grand Prix saw horsepower decrease. With GM corporate downsizing in the late-1970s, the Grand Prix followed by adopting the new 108-inch wheelbase A-body. Much more conservative with less sculpturing than the previous A-body, nevertheless sales ratcheted up to over 228,000 GP’s sold, and ended 1979 with a similar production of over 210,000 units sold.
1978 Grand Prix
With GM corporate downsizing starting in 1977, the A-body’s turn was 1978. A more conservative, less sculptured body was the result—which was 12-inches shorter and 600-pounds lighter than the 1977. A new Buick-built 231ci V6 was now available, and also a new manual three-speed with floor shift. Interiors could be ordered in cloth, “pillowed” velour, or leather. GM was headed for a problem because not only was it getting harder to tell the difference between the Lemans and Grand Prix, but it was becoming increasingly difficult to tell an A-body Olds Cutlass from a Buick Regal from a Grand Prix.
AVAILABLE MODELS:
1978 Grand Prix
- Body Style
- 2-Door Notchback Sport Coupe
- Engine Options
- 231-2bbl cubic inch V6, 105hp
- 301-2bbl cubic inch V8, 135hp
- 301-2bbl cubic inch V8, 150hp
- 305-2bbl cubic inch V8, 135hp (California only)
- 350-4bbl cubic inch, 160hp
- 350-4bbl cubic inch, 170hp (California only)
- 400-4bbl cubic inch, 180hp
- 403-4bbl cubic inch, 185hp (California only)
1978 Grand Prix VIN Decoder:
First Character: GM Division
Second Character: Series
- H ~ Grand Prix SJ
- J ~ Grand Prix
- K ~ Grand Prix LJ
Third and Fourth Characters: Body Style
- 37 ~ 2-Door Notchback Sport Coupe
Fifth Character: Engine
- A ~ 231-2bbl
- H ~ 305-2bbl
- U ~ 305-2bbl
- L ~ 350-4bbl
- R ~ 350-4bbl
- W ~ 301-2bbl
- Z ~ 400-4bbl
- K ~ 403-4bbl
Sixth Character: Model Year
Seventh Character: Assembly Plant
- P ~ Pontiac, Michigan
- Q ~ Detroit, Michigan
- A ~ Atlanta, Georgia
- B ~ Baltimore, Maryland
- J ~ Janesville, Wisconsin
- K ~ Leeds, Missouri
- L ~ Van Nuys, California
- C ~ South Gate, California
- D ~ Doraville, Georgia
- E ~ Linden, New Jersey
- R ~ Arlington, Texas
- S ~ St. Louis, Missouri
- T ~ Tarrytown, New York
- U ~ Lordstown, Ohio
- W ~ Willow Run, Michigan
- X ~ Kansas City, Kansas
- N ~ Norwood, Ohio
- G ~ Framingham, Massachusetts
- Z ~ Freemont, California
- 1 ~ Oshawa, Ontario, Canada
- 2 ~ St. Therese, Quebec, Canada
Fifth through Eighth Characters: Basic Production Numbers
The sequential starting numbers.
Big Bonus!