The colloquial term "Ferguson 28" is sometimes used in Australia and New Zealand for later models of the TE-20 including the petrol TEA-20 and diesel TEF-20.[citation needed] "Ferguson 28" has never been an official tractor model designation. Initially the TE20 had the 'Continental' Z120 23HP engine, as did the Detroit-built TO20 introduced a year later. The 80 mm bore 'Standard' petrol engine was phased in in mid-1947 as the TEA-20, approximately 3,000 of the 20,500 tractors built to 31 December 1947 being TEA-20s. Subsequent to the introduction of the 85 mm bore TED-20 in April 1949, the petrol engine was also made with an 85 mm bore, which increased its power to just over 28 hp. The term "Fergie 28" refers to the nominal horsepower of the later range of tractors. To benefit from the reputation of the later models in the used tractor market, the 23HP TE-20 is often advertised simply as TE-20; only very rarely is it referred to in Australia as a "Ferguson 23". In North America the 'Standard' petrol-engined TEA-20s with the 85 mm bore were known and advertised as TE-2085s.