“Motor head” is a slang, akin to “gear head”.

I get it. He is going to wear the tesla sparker as a hat.

 

I have no idea why they call it a SRSG (synchronous rotary spark gap)

It's been a while since I thought of this stuff, but if I remember right it is used to make sure the output is in sync with the input sine wave zero crossing of the power in the gap. Again I think.