Founded in 1965 by Burkard Bovensiepen in Kaufbeuren, Bavaria, the German firm of Alpina began producing tuned versions of BMW models in the 1960s before BMW's own Motorsport Department launched its now famous 'M' range.

A close collaborator with BMW from its earliest days, Alpina enjoys motor manufacturer status in Germany and can take much of the credit for establishing BMW's high performance image thanks to a succession of sensational road cars and countless race-track victories.

This rare Alpina model is based on the BMW 635CSi (E24 chassis).

Mechanically similar to the 5-Series saloons, BMW's 6-series coupé debuted in 1976 incorporating some components destined for the yet-to-be-announced 7-Series.

Karmann styled like the preceding 3.0CS/CSi, the newcomer was similarly well-specified, featuring all-independent suspension, four-wheel disc brakes and power-assisted steering as standard.

The existing 2,985cc, overhead-camshaft six was carried over to the 630, the latter becoming...