1972 saw the introduction of SD's new 'N' Series chassis with a modified steel cab made by Motor Panels. The floor and rear wall were added by Shelvoke, as well as a taller fiberglass roof. This was a departure for SD, having traditionally built their own cab. The majority of Revopak bodies built in the 1970s would be mated with the 'N' series. A new 'NT' series joined the line, giving SD their own production-model tandem-axle chassis for larger bodies, without having to use outside makes like Leyland or Ford. The Pakamatic refuse body remained in production, and was available on the 'N' series for a few more years.
    The 'NN' and 'NL' series were a narrow-width, short-wheelbase version, which retained the old 'T' series coachwork. The limited production of these necessitated keeping the old cab around for a few more years. The 'NN' series tanker/gully emptier line followed suit through the mid-1970s, while 'NX' and 'NY' tankers received the Motor Panels cab.
The new 'N' series was the first to use non-Shelvoke cab
Series 'NT', the first Shelvoke and Drewry tandem-axle model
    Even with the introduction of the modern looking 'N' Series, the older style cab design was to live on during the 1970s, first with 'NN' (shown above) and 'NL' series Revopak, a compact version designed for narrow streets and congested areas. These effectively replaced the old 'TN' Pakamatics of the 1960s, which met the same need.
Likewise, the smaller 'NN' 1100/1500 tankers also kept the old 'T' Type coachwork
Above: What might have been; 'N' Series Revopak for the United States market (Wayne Engineering) with a lowered rave rail, and tested during the 1970s. Virtually unknown in America, the Revopak could have potentially found many American customers back in the 1960s. However, tightening safety regulations during the 1970s probably killed the U.S. version, and would spell the end for revolving packers everywhere in a few years. Wayne ultimately chose the Swedish Norba screw-type loader.
Progress With SD (1973 Factory Film)
Part 1 of 5 below:
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