95 Sable Starter Bolt removal

Hello. I have a 95 Sable wagon 3.8 L . I am trying to remove the starter. The bolt in th e fron is the problem bolt. It has an extended shaft for ground wire connections. Well, OK - here is the problem. The bolt is in a tight area and when I can get a box head wrench around it even with a pipe lever When I try to wrench it off. it seems to want to strip rather than budge. Yes, I tried deep set sockets but they dont fight right. maybe the edges of the bolt are too rounded.

So here is the question. has anybody out there had this problem and is there a good lead to some kind of a strap wrench that self adjusts to the bolt? It would have to be rather slim as the space available is very tight. I wresled with that darn bolt ALL day and night yesterday and sheesh it is really frozen on there. The frustrating thing is I put it on myself about 4 years ago and now I am stuck in the mud with a frozen bolt that won't budge and the edges seems soft to the turn. anybody out there that was up against this beast of a bolt and if so what did you do? Thanks.