Before 911 production commenced in 1964, the Porsche Vehicle Research Department had set aside chassis numbers 13328, 13329, 13330, 13352, and 13386 through 13397 for research testing of the 902; research vehicle Serial Number 13394 is the oldest 902 known to exist today. In production form, the Type 912 combined a 911 chassis / bodyshell with the 1.6L, four-cylinder, push-rod Type 616/36 engine, based upon the Type 616/16 engine used in the Type 356SC of 1964-1965. With a lower compression ratio and new Solex carburetors, the Type 616/36 engine produced five less horsepower than the 616/16, but delivered about the same maximum torque at 3,500 rpm versus 4,200 rpm for the 616/16. Compared to the 911, the resulting production Type 912 vehicle demonstrated superior weight distribution, handling, and range. To bring 912 pricing close to the 356, Porsche also removed some features standard on the 911. As production of the 356 concluded in 1965, on April 5, 1965 Porsche officially began production of the 912 coupé. Styling, performance, quality construction, reliability, and price made the 912 a very attractive buy to both new and old customers, and it substantially outsold the 911 during the first few years of production. Porsche produced nearly 30,000 912 coupé units and about 2500 912 Targa body style units (Porsche's patented variation of a cabriolet) during a five-year manufacturing run.