'85 5kT starter ???

[Ameer Antar]

I'm trying to get at the wastegate downpipe connection, but the starter is
in the way. But it looks different from my previous 5kT. I can only see one
bolt at the bottom of the starter baseplate. But it's not even really a
bolt head...It just looks like a sliver of a bolt head. The head is about
1/2" long and 3/8" wide. I've never seen that before, and I have no idea
what tool to use on it. I tried budging it with a hammer and punch. It
seemed to move a little, but not anymore. What the hell is this thing, and
what's supposed to be used on it??!!! Thanks in advance.

-ameer