I know they came out before ST was moved to China, but the S series of engines was 2 generations of engines ago. So the tooling for those could have been moved long before that. This also explains why Tower can sell them so cheap. These engines do strongly resemble the ST's from the early to mid 80's. My Tower 60 crank case is almost Identical to the ST S60 I have from 1982. All the porting and timing look about the same too. In the late 70's to early 80's ST was known as a hot engine, especially the Series X motors with the PDP porting in them.

1. No R&D costs.
2. Made in China where labor is 10 cents a week.

Maybe the Hobico rep can give us some insight on this, Tower does fall under the same corporate banner, even if they won't acknowledge it publicly. LOL (Area 51) LOL