Question: What engine designed to power medium duty trucks and heavy cars was also used in Chevy's intermediate and pony car?
Context: The L72 was a Big-Block engine produced by Chevrolet between 1966 and 1969.  Initially rated at 450 horsepower, the rating dropped to 425 horsepower shortly after its release (although there was no change in power).  In 1966 it was the most powerful engine available in the Corvette, and between 1966 and 1969 was the most powerful engine available in full-sized models.  In 1969 the L72 was available via a Central Office Production Order (COPO) in Chevrolet's intermediate (Chevelle) and pony car (Camaro).  Today these vehicles - referred to as COPOs - are among the most collectible 1960s performance cars. The Muncie SM465 is a heavy-duty, four-speed manual transmission built by General Motors for use in light and medium duty trucks from 1968 to 1991.  The SM465 can be found in Chevrolet and GMC full-size trucks, Blazers, Suburbans, among other models.  Some applications beyond one-ton pickup trucks came with larger input shafts.  Favored by off-road drivers, the SM465 has a very low first gear suitable for rock-crawling.  The SM465 has developed a reputation as a highly durable transmission.  For the 1992 model-year, the SM465 was replaced in 3/4- and 1-ton pickup truck applications by the New Venture Gear 4500 transmission. The Chevrolet "Big Block" is a term for a series of large displacement V8 engines that have been developed and produced in the United States from the 1950s to the current day.  As American automobiles grew in size and weight following the Second World War, the engines powering them had to keep pace.  Chevrolet had introduced its popular small block V8 in 1955, but needed something larger to power its medium duty trucks and the heavier cars that were on the drawing board. The Renault Trucks D is a range of medium duty trucks for distribution manufactured by the French truckmaker Renault Trucks.  It was launched in 2013 to replace the Midlum, the Premium Distribution and the Access. The Dodge Challenger is the name of four different generations of American automobiles (two of those being pony cars) produced by Dodge in Detroit, Michigan.  The Dodge Silver Challenger was produced from 1958 to 1959, as a version of the full-sized Dodge Coronet sedan.  From MY 1970 to 1974, the second generation Dodge Challenger pony car was built using the Chrysler E platform, sharing major components with the Plymouth Barracuda.  The third generation, from 1978 to 1983, was a badge engineered Mitsubishi Galant Lambda compact car.  The fourth, and current generation is a pony car introduced in early 2008 as a rival to the evolved fifth generation Ford Mustang and the fifth generation Chevrolet Camaro. The DAF LF is a range of light/medium duty trucks produced by the Dutch manufacturer DAF and assembled by Leyland Trucks.  It is a redevelopment from the Leyland Roadrunner of 1984. Pontiac West Assembly was one of several General Motors assembly plants in Pontiac, Michigan located along South Boulevard West and Franklin Road.  It was originally called the Rapid Motor Vehicle Company until 1909 when GM acquired the company, renaming it GMC.  It served as the original location of GM trucks, including military equipment for World War II.  In 1972, it was joined by a new facility, called Pontiac East Assembly that built GMC and Chevrolet medium duty trucks and buses. The International TerraStar is a product line of medium duty trucks that was manufactured by International Trucks from 2010 to 2015.  The smallest conventional-cab truck ever produced by Navistar, the TerraStar is a Class 5 medium-duty truck.  Although not officially designated by the company as the replacement for the CityStar LCF cabover, the TerraStar is of similar dimensions and GWVR.  Slotted in the Class 5 range, the TerraStar was marketed against both pickup-based vehicles like the Ford F-550 and (Dodge) Ram 5500 as well as conventional-cab trucks like the Freightliner M2 (smallest versions), Kenworth T170, and Hino 185. The Isuzu 6H is an inline-6 cylinder Diesel engine installed in Isuzu medium duty trucks, and also installed in GM medium-duty trucks as the Duramax LG4.  It is mated to the Allison 2500, 3000 and 3500 Series transmissions. The Renault Trucks C is a range of medium duty/high duty trucks for construction manufactured by the French truckmaker Renault Trucks and introduced in 2013.
Answer: The Chevrolet "Big Block"