It's a fabulous little engine and gave rise to many other very exotic, and somewhat obscure variants including the Brabham Repco F1 engine (with DOHC heads) and with 2 cylinders lopped off formed the base of the 3 litre V6 found in the Metro 6R4 Group B Rally Car (developed I think by Williams F1 from memory). They could chuck out 400 very reliable N/A horsepower sounding glorious, and even as far as the mighty V6 twin turbo in the all conquering Tony Southgate (Le Mans/IMSA?)Jaguars, all had in some way, some DNA found in the the original Buick/Rover.
E&OE