For all the info on the web for pinball, there is suprisingly very little about Sega Pinball machines from the 70s. They made EMs and eventually went to SS but there are very few in the U.S. I've been digging looking for some examples and gameplay video. There is (was?) a Japan Pinball Museum located in Osaka that has quite a few examples.
Here's a EM bowling game that is pretty neat.
They look at a few more Sega pinball backglasses and machines before playing a EM driving game and a pretty neat mechanical music machine at the end.
The one EM game has an 8 track running the sound.
The pinballs look like they have pretty simple gameplay but have some neat gimmicks like the slalom in Sapporo.