4. In 1984, Mazda claimed its fifth straight manufacturer's title - an IMSA record.
In 1984, Ira Young, owner of the Malibu Grand Prix racing team in the US, bought Jim Downing's 1982 champion RX-7 and continued to race it in the GTU class. His main driver was Jack Baldwin, with Young himself as co-driver for endurance events. Together, they won the first round Daytona 24-hour race. Baldwin didn't retire from any of the season's 17 races, managing a top-five finish in all but one, and was duly crowned champion. Thanks to the RX-7, Mazda surpassed Porsche's record by becoming the first manufacturer in IMSA history to win five consecutive titles.