Are you the one that pitched yeast in the high 70s. I'm actually concerned that you have a stuck fermentation here because I think you might have pitched at a high temp but the ambient was much lower as I recall. This could result in too much alcohol too fast coupled with a big temperature drop compromising the yeast.
I am worried about bottle bombs. I really think you should sacrifice a bottle and do a fast ferment test to make sure it's done, taking into account priming sugar. If there is a significant drop in gravity and the yeast was only dormant and not dead you could have a dangerous problem.
I think the problem here was the high temp pitch. You should bring it down closer to fermentation temperature before pitching. If you pitch in the high seventies and store in the sixties ambient the yeast activity will initially heat up the fermenter into the mid eighties, ferment most of the sugar but not all then as the activity lessens it will fall to ambient. For big beers it is actually better to warm it up a little as Krausen ends to help finish.
It would also be good to see your grain bill.