Which is why Leyland Australia were developing the V6. Being based on the P76 V8 (which was basically a 4.4 litre version of the Rover V8), the Marina V6 was an alloy engine and was very light - lighter than the 4 cylinder E Series in fact, which would have made the Marina Six a much better balanced car and markedly improved its handling. Australian four cylinder Marinas actually handled better than UK built cars, due to the use of the E Series instead of the old heavy B Series engines. Because the 4 cylinder E Series was originally designed for East-West installation, the Australian engineers designed a new bell housing before mating it with either a Triumph manual gearbox or a locally made Borg Warner automatic. The V6 was to have been 3310cc. The prototype engine was running on a dynamometer in October 1974 and, when it became obvious that Leyland had no future as a manufacturer in Australia, the prototype engine was sent to Rover in Coventry, as Land Rover had shown an interest in it. Had things been different and the V6 went into production, it would have also replaced the in-line six in the six cylinder P76.
Australian Marinas, incidentally, were shipped in CKD form to South Africa, for assembly there.
And did you know that BMC Australia had earlier built a V8 version of the Austin 1800? The experience from that was partly why they built the P76 as a rear wheel drive car.....