sklinck1 Wrote:
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> Why do the 2 16-645 engines in a DDA40 produce
> 3,300 horsepower each when the same engines in an
> SD40 only produce 3,000? Are the DDA engines
> governed differently or something?

Well, for one thing they are NOT the "same engines". The SD40 model (note, you didn't state SD40-2) was the 16-645E3 model, which produced about 3250 HP at 900 RPM (thus, 3000 HP for traction). The DDA40X (please note the CORRECT model designation), was the forerunner, i.e. experimental, for the "Dash 2" line of units with the modular control circuits, which debuted in 1972. The engines in the DDA40X were the 16-645E3A version with almost 3500 HP gross, at 950 RPM, thus 3300 HP for traction.