The 1966 Season

Hailed as the "return to power" the 1966 season saw the start of the new 3 litre formula.
Some teams were more ready than others and as a consequence a wide variety of engines and chassis were used ranging from Ferrari's new purpose built 3 litre V12 (312) to modified 65 season engines which were bored out to 2 litres.
There were also various 4 cylinder Climax engines plus a 2.4 litre V6 (246) Ferrari based on the "Dino" engine.

Anglo American Racers

The Eagle T1G designed by Len Terry for Dan Gurney's "Anglo American Racers" started the 1966 season powered by a 2.7 litre 4 cylinder Climax engine with which Gurney had some success, being placed 5th at the French and Mexican Grand Prix and a 7th at the German Grand Prix.
The Climax engine was always intended as a stop gap because Gurney has commissioned Harry Weslake to build him a brand new 3 litre V12 engine. The Weslake V12 eventually arrived late in the season to make an appearance at Monza and Watkins Glen but reliability issues meant Gurney running the last race of the season with the sturdy and reliable Climax unit.