Cosworth received an order from Ford in the late 1960's to produce a competitive Formula 1 engine, along with the £100,000 that Ford felt it adequate to spend on such an objective. During the 1970's it was not uncommon for almost the entire field (barring [[Ferrari}} to be using one of these engines (This at a time when independent wealthy individuals could buy exactly the same engine off the shelf that was also being used by McLaren et al).
The engine was modified to keep abreast of the regulations, and steady development caused the final power output to be almost double that of the earlier variants. It was the advent of turbocharged engines in Formula 1 which sounded the death knell for the venerable DFV.