The McLaren M4A Formula 2 car was designed by Robin Herd and announced in early 1967. It was to be built by Lambretta-Trojan. The M4B was the Trojan production car for the American Formula B racing series. Between 1967 and 1968, there were twenty-five examples of the M4 built.

The M4B had a ten-gallon fuel tank on either side of the cockpit with an additional 5 gallons in a seat-back tank. The car had a bathtub monocoque formed from aluminum paneling which was attached to four steel bulkheads. The nose and cockpit were clothed in fiberglass. At all four corners were McLaren Elva cast magnesium wheels that measured thirteen inches high and seven inches wide.

M4B F1

The McLaren M4B was designed by Robin Herd and developed from one of the M4A cars. It was McLaren's second F1 championship contender, and it contested two world championship races. It also raced at several other events. Powering the M4B was a 2.1-liter BRM V8, which helped it score three points in its short-lived competition career. All of the points were scored at the second championship race at Monaco.

The M4B was an improved version of the M4A Formula Two car with a larger engine and fuel tanks. It made its racing debut in the 1967 Race of Champions at Brand Hatch. The car showed tremendous promise, but after missing a gear while shifting, Bruce had to retire prematurely from the race due to engine failure. At the Spring Trophy at Oulton Park, McLaren finished in fifth place in both heats of the race. He scored another fifth in the International Trophy at Silverstone.

The car's Grand Prix racing debut was at the Monaco Grand Prix where Bruce may have finished in either second or third had it not been a problem with the batter that caused him to pit for a new one. This cost him two places; he finished fourth.

At the next event, the Dutch Grand Prix, the M4B was outclassed by a field that was powered by a new Cosworth DFV engine. Bruce finished 14th in qualifying. On the second lap of the race, Bruce crashed out, ruining the only M4B. The car was later repaired, but it caught fire during a test at Goodwood and was written off.

For the 1967 season, McLaren introduced their next F1 contender, the M5A.

by Dan Vaughan