In 1958 the Birmingham Scott was updated by adding a swinging arm frame and the dynamo was replaced by an alternator. A new 493 cc motorcycle called the Scott Swift was announced but never went into production, although Holder continued to develop and produce one-off Scott motorcycles until 1978. Fabricator Brian Bulmer teamed up with two-stroke engine tuner Brian Wolley and rider Barrie Scully to develop a racing version of the Birmingham Scott air-cooled 350 cc twin, setting a record for the Barbon Hill Climb and achieving in a "Motor Cycling" test. The team also developed a 52 bhp water-cooled 500 cc version, but competition from Japanese two-strokes meant that the project was not fully developed. The 1970s also saw the launch of the George Silk Scott. Effectively one-off bespoke motorcycles, only about 22 were produced in the late 1960s and early 1970s, with the last being made in 1975. This incorporated the old Scott engine accommodated into a modern Spondon frame. In the 1930s Scott manufactured a number of stationary engines with the aim of raising funds following the decline in motorcycle sales. Some of these engines were derived from motorcycle units, for instance the DSE was a watercooled version of the Lightweight Squirrel engine and the SE had the same bore and stroke dimensions as the long stroke Flyers. It has come to light that the SE does not have the same bore size as the Long Stroke Flyer (73 mm) but has a bore size of 78 mm, this has been confirmed on two Scott SE engines. The PA stationary engine however was different. Designed to meet a Ministry requirement for a portable electrical generator for the Bofors anti-aircraft gun and its Kerrison Predictor, it was produced during the Second World War by both Scott and its former partners Jowett. It was air-cooled, petroil-lubricated and featured a loop scavenge design with two opposed main transfer ports supplemented by a third "boost" port opposite the exhaust. This arrangement was patented by Scott in 1939, but is often mistakenly believed to be of post-war origin as it was later widely adopted for motorcycle racing engines and power boats after its reinvention in the late 1950s by East German motorcycle manufacturer MZ.