RE: O.S. Engines-Model differences???
Neat! I'd never seen some of those engines on there.
Those dates are likely the dates when they began producing those engines in Japan, but not when they began importing them into the US. That page shows the .91 Surpass II and 1.20 Surpass III as debuting in 1996. I am positive they did not appear here until late 1999 or early 2000.