In the 1970s, Ford designed and produced a small-block engine with hemispherical heads to address the growing concerns about fuel economy. Unfortunately, even with an ahead-of-its-time direct fuel injection system feeding a stratified charge chamber, the hemi's emissions could not be made clean enough for compliance with regulations. This plus the cost of the valve actuation systems, along with the cost of the high pressure pump needed to deliver fuel directly into the chamber, as well as the gilmer belt drive system needed to drive the pump, made further development pointless at the time. Most 1980s 4-cylinder Fords used the Ford CVH engine, CVH meaning "Compound Valve, Hemispherical (Head)".