Along with Oldsmobile, Pontiac had the distinction of having all three of General Motors' mainstream platforms in 1940, but this would last only one more year. In 1940 Pontiac introduced its first B-bodied car, the Deluxe Series 28 Eight. Also in 1940, Pontiac introduced the Torpedo on the C-body. The new C-body featured cutting-edge "torpedo" styling. Shoulder and hip room was over 5 in (127 mm) wider, running boards were eliminated and the exterior was streamlined and 2–3 in (51–76 mm) lower. When combined with a column mounted shift lever the cars offered true six passenger comfort. These changes had clearly been influenced by the Cadillac Sixty Special.
In 1941 the A-body and B-body were similarly redesigned. Consequently Pontiac renamed its entire line-up "Torpedo", with models ranging from the low-end A-bodied Deluxe Torpedo (with a 119.0 in (3,023 mm) wheelbase), the mid-level B-bodied Streamliner Torpedo (with a 122.0 in (3,099 mm) wheelbase up 2.0 in (51 mm) from the previous year), and the high-end C-bodied Custom Torpedo (with the same 122.0 in (3,099 mm) wheelbase as the previous year).
1941 was the last year Pontiac offered a model with the GM C-body until the big "Clamshell" tailgate Pontiac Safari and Grand Safari station wagons of 1971-76. For 1942, the Torpedo name was assigned to the A-bodied Pontiac while the Streamliner became the B-bodied Pontiac.
Streamliners used the larger B-body and, except for the station wagons, used fastback styling. The 1941 Super models with folding center armrest were known as Chieftains in 1942. All Pontiacs looked lower, heavier and wider. Extension caps on the on the front doors lengthened the forward fender lines. The hood extended back to the front doors, eliminating the cowl. The grille, bumper and hood were widened and headlamps were further apart. Long horizontal parking lamps sat just above the vertical side grilles. The horseshoe shaped center grille had horizontal bars and a circular emblem in the middle of the upper main surround molding. The word Pontiac appeared on the hood side molding of six-cylinder models, while the moldings of the eight-cylinder cars said Pontiac Eight. After December 15, 1941, wartime "blackout" trim was used. All parts previously chrome plated were finished in Duco Gun Metal Grey.
With the end of the C-body Pontiac Custom Torpedo, station wagon production was transferred to the new Streamliner line. The final body work continued to be done at either the Hercules Body Company or at Ionia Manufacturing. The Streamliner station wagon ranged from $1265 for a base Six to $1340 for a Chieftain Eight, making it Pontiac's most expensive model. At 215.8 in (5,481 mm) in overall length the 1942 Pontiac Streamliner station wagon also set a record for the longest Pontiac that would not be exceeded until the 1959 Pontiac Star Chief and Bonneville.
The first postwar Pontiac available (September 13, 1945) was the Streamliner coupe, which remained the sole product for a time. The Chieftain trim level of 1942 was renamed the Deluxe trim level in 1946. Styling highlights of Pontiacs were wraparound bumpers, a massive 14 blade grille, new nameplates and concealed safe-light parking lamps. Streamliners could be identified by straight back Indian moldings on the rear hood ornament chrome beltline moldings and bright moldings on the "speedline" fender ribs. They also had longer front fender crown moldings and were generally larger in size. Lettering on hood emblems and badges placed forward of the "speedlines" identified Eights. Interior trim on passenger cars were in gray striped cloth. Station wagons had three seats in standard trim, two seats in Deluxe trim and used imitation leather upholstery and passenger car style interior hardware. Ranging in price from $1942 for a standard Six to $2047 for a Deluxe Eight, Streamliner station wagons continued to be the most expensive Pontiac model. A total of 92,731 Streamliners were sold in 1946, accounting for over two thirds of all Pontiacs.
In 1947 the "Silver Streak" styling theme was continued, now with five bands of chrome on hoods. All Pontiacs had new grilles with four broad gently bowed horizontal bars. Hoods and fenders were protected by an inverted steer's horn shaped bar incorporating a die cast plate with indianhead relief. Interiors for sedans and coupes were redesigned with Berwicke beige panels for dashboard and windows. Windshield, door and garnish moldings were finished in Autumn Brown with dado stripe border moldings. All coupes and sedans were fastbacks with full-loop around window moldings. Streamliner station wagons ranged in price from $1992 for a standard Six to $2111 for a Deluxe Eight, again making them Pontiac's most expensive model. Sales of Streamliners totaled 128,660 in 1947, or nearly 56% of all Pontiacs sold.
In 1948 a new Pontiac styling included triple "Silver Streaks," a horizontal grille theme with vertical shaft, and round taillights. The word "Silver Streak" was carried on the sides of the hood with eights having an "8" placed between the two words. Streamliners were again larger and more expensive than other Pontiacs. All Streamliners, be they 2-door or 4-door fastbacks, or station wagons, now came standard or Deluxe. Deluxe models were destinguished by spear moldings on front fender, bright gravel guards, and chrome plated wheel discs on all cars except wagons. Deluxe interiors had two tone trims with pillow-and-tuft seatbacks, quarter sawed mahogany dash and window trim, electric glovebox door clocks, Deluxe steering wheels and other rich appointments. Standard Streamliner station wagons had tan imitation leather seats and Deluxe wagons had red upholstery of the same type. Station wagon prices ranged from $2364 for a standard Six to $2490 for a Deluxe Eight, making them Pontiac's most expensive model. In 1948 160,857 Streamliners were sold, accounting for nearly 66% of all Pontiacs.
Perhaps the biggest story of 1948 for Pontiac was the addition of Hydramatic automatic transmission as an option. As of 1948 only General Motors sold cars with fully automatic transmissions and the only other way to get one was to buy a higher priced Cadillac, Buick or Oldsmobile. Chevrolet would not introduce Powerglide until 1950, Ford FordoMatic until 1951 (Lincoln would start buying Hydramatics from GM in 1949), and Chrysler, PowerFlite on Imperials, until 1953. Hydramatic proved very popular with a total of 171,946 Pontiacs sold with it, or about 71% of all Pontiacs, and with 122,327 Streamliners equipped with it, or about 76% of all Streamliners, in its first year. Since Hydramatic was still only optional on Cadillac and Oldsmobile, and Dynaflow optional on Buick Roadmaster, given the total sales of Cadillac (50,619), Oldsmobile (173,661) and Buick Roadmaster (80,071), and the fact that Dynaflow was only introduced in the middle of the model year, this implies that probably over 40% of all cars sold with automatic transmissions in 1948 were Pontiacs.
The 1949 Pontiacs featured low sleek envelope bodies. Streamliner coupes and sedans utilized the fastback B-body shell. Station wagons continued to be part of the Streamliner line. All of these cars came as standards or Deluxes. All station wagons and other standard models had small hubcaps. Standard coupes, sedans, and wagons were characterized by an absence of beltline trim along with use of rubber gravel guards and painted headlight rims. Deluxes had beltline moldings, chrome gravel guards and bright plated headlight doors. Silver Streak styling was seen again. Silver Streak lettering was placed above front fender spears on Deluxes and high on the fenders of standards. Eights had the number "8" between the two words. Most standard models had gray striped pattern cloth upholstery. Most Deluxes used dark gray broadcloth trims. Wagons were trimmed as before except imitation leather was only used on standard wagons. 1949 was the last year for wood-bodied station wagons, as production shifted to all-metal station wagons with woodgrain trim during the model year. Streamliner station wagons continued to be the most expensive Pontiac model, ranging in price from $2543 for a standard Six to $2690 for a Deluxe Eight.
The 1950 Pontiacs utilized the popular 1949 envelope bodies with revisions to trim and appointments. The horizontal center grille bar now wrapped around the corners of the body. Deluxes had a chrome body strip, chrome wheel rings, chrome headlight rings and stainless steel gravel guards. Eights had an "8" between the words. Streamliners (except for station wagons and sedan delivery trucks) had fastback styling. The price of Streamliner station wagons fell to a range of $2264 for standard Sixes to $2411 for Deluxe Eights due to the fact all-metal construction did not require final work be done at Hercules Body Company or Iona Manufacturing. Nevertheless, the Streamliner station wagon remained the most expensive Pontiac model.
The 1951 "Silver Anniversary" Pontiacs reflected 25 years of advanced engineering. A wing shaped grille was seen and a Silver Streak theme continued. Streamliners again used the B-body shell with sloping fastbacks on coupes. Deluxes had chrome body strip, bright gravel guards, and headlight rings. Belt line moldings on all Deluxe passenger cars (not station wagons) had a dip behind the doors. Standard belt moldings were straight. A script plate reading Pontiac was used on Series 25 Sixes and on Series 27 Eights a different script read Pontiac Eight. In its final year, the Streamliner station wagon continued to be Pontiac's most expensive model, ranging in price from $2470 for a standard Six to $2629 for a Deluxe Eight. Pontiac's headquarter operations at the Pontiac, Michigan plant was responsible for 49.2% of all Pontiacs built in 1951.
With the demise of the Streamliner, 1951 would be the last time Pontiac offered a B-bodied car until 1959.