NGA is the MK1/2 Mondeo Silvertop 2,0 Zetec-E engine.

When the Focus was introduced in August '98 also the last MK2 Mondeos got the Blacktop engine. Ford switched to (all) 4-digit engine codes at this time, but kept the old 3-digit ones in cars like the Mondeo that were still in production.

NGB, NGC and NGD were all 2,0 Blacktop engines in the Mondeo MK2.

Focus 2,0 Blacktop were EDDB, EDDC, EDDD and EDDF; Duratec-ST (ST170) was ALDA, Duratec-RS was HMDA

Cougar 2,0 Blacktop were EDBA, EDBC and EDBD