Block-mounted starters came along in the mid-70's, I believe. The earlier ones had a 3-bolt flange mount that bolted to the bellhousing.

The mini-starters are Japanese-made, and they use a planetary gear reduction to let the motor armature run at higher speed than a direct drive starter. They sound funny, but they do a pretty good job of cranking the engine. I don't think I've ever seen one that has a bellhousing mount, but there's no reason it couldn't be set up that way.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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