
That would be the Opel GT, sold in this country from '69 to '73.  It originally
had a 1100 cc engine, which was later replaced by the 1900 cc.  It was based
on the old Kadett drive train and suspension, with leaf springs in the rear
and a single transverse leaf spring in the front.  It looked good, but was
limited as a performer.

There has also been some discussion in this thread about the Manta and other
models.  In 1971 Opel introduced a new line of models, the 1900 series, that
were also known as model numbers 51, 57, etc.  These cars had the newer
1900cc engine and were available as two and four-door coupes, a station wagon,
and a "sport coupe", known in Europe as the Manta.  At the same time, there
were two 30-series cars, which sold very few numbers, that also had the 1900
engine but the Kadett suspension.  The sport coupe, (model 57) was also
available as the Rallye, (57R), with a blacked out hood, tach, and fog lights,
but was mechanically the same except for a numerically higher rear end ratio.

In 1973 the sport coupe was also named the Manta in the US.  1973 was the last
year for the GT in any country, both because of the US bumper height regulations
and the fact that FIAT exercised an option on the factory that Opel was leasing
to build the GTs.

The 1900 series continued in 1974 with minor body differences.  In 1975, the
Manta, 1900 sedan (also called the Ascona) and the wagon were available with
Bosch electronic fuel injection.  These cars also had larger brakes and
wider wheels.  These cars were starting to compete with the 1975 Buick Century
low price leader of the time, and were the last Opels imported into the US.

From 1976 to 1979, cars that sported Buick/Opel badges were still sold by
the Buick dealers, but were rebadged Isuzu I-marks.  The idea was to call them
Opels instead of changing the dealers' neon signs.

Various models of the 50-series cars dominated the Showroom Stock racing of the
70's in their class, and were known as serious 2002-competition.

Parts are still available from a number of sources.

(I still have a '73 manta and two '75 sedans and all the trick parts I could
collect in 20 years).