Nice grinder! I brought home an old 8" Delta from the mill that looked like that. Motor wouldn't start, just hummed and locked up, start winding wasn't engaging or was cooked. So they gave it to me, turned out it was fried though and there was nothing I could do. So I stripped what parts I could from it and chucked the main motor/arbor part.
Something that works good for a grinder stand base is a big old chain sprocket. We have many at the mill that are a good 1" thick and 18" diameter or more; they sit perfectly flat and solid and are NICE and heavy. I see worn-out ones come into our scrapyard from the various mills and mines all the time here, not sure what they'd want to buy one.