65 cuda 273 upper starter bolt

Still finding stuff to fix on this very nice 65 Barracuda I picked up a couple months ago. I'm sure that's endless - that's why I bought it. Anyway - the upper starter bolt was only finger tight. I tried open and box end wrenches, sockets, universals, etc. What's the trick to get a tool on this to tighten it? It's 11/16 hex. Looks like it would be easy with column out.
I do not have any experience with this problem but do you have any of the old curved starter box wrenches or are you familiar with them? Just a thought. yeah, I am an "old guy"! :)