Hi Roger,

Lot's of reasons. Mostly economy of scale. First, ZDZ's aren't made in the US; exchange rates, labor costs, etc. all help the ZDZ's cost. Secondly, they are mass-produced engines, Taurus' are not, and that's one of the reason's Taurus is able to control the tolerances and consistantly produce engines of extremely high quality. I know this opens the same can of worms again about quality, and relative power. First I will say that I really like ZDZ's, and for specific applications I wouldn't hesitate to own one, as a matter of fact I have a ZDZ80 for a H9 Cap, but after owning both, my opinion is that Taurus' are of higher quality than the ZDZ's and specifically with the TS-42 vs ZDZ40, the Taurus has measurably more power.

This all makes sense. If someone can take the time to hand build a well designed engine with closely controlled tolerances, and individually test and tune that motor, it is likely to come out superior in smoothness and power to other motors that were not made this way....even if on paper the other motor has a more "advanced" design, such as the ZDZ's rotary valve multi-port design would appear to have.