I have a pic of the staggered bolt starter I could use on the left and the one in question on the right. The hole in my Lakewood block plate won't allow the left starter to go on. The starter on the right will go on, but if it's an oddball, no longer available part, I'll have to go another route.
I have seen a couple, crawling through boneyards. Not sure where they are from, or exactly which flywheel/flexplate they fit, sorry. Starters are rebuildable, unless something is really, really wrong. Hell, you might be able to swap snouts.
65 to 70 or so big block (non corvette) and yes all gm starters are the same -if your stuck, just swap the cast iron nose onto the more common aluminum nosed one.......same motor etc.....
I have one on my 75 Corvette 350 4-speed If you look at Eckler's Corvette it has a picture of that starter. It fit's 65 to 82 big and small block $263.00
Thanks to all, that is good news. I figured that I stashed it for a reason; I just couldn't remember what it came off of. Thanks for the link,squirrel.