Imagine if you kept the -5's and went e85 like you had originally planned, that shit could have gone really wrong spinning that thing hard. Personally i would be trying to find his mobile/home number and chatting with him to see what he says. Generally i would have given him the benefit of the doubt and his builder had rolled him, however his shady actions hint other wise (blocking you, not replying etc)
On another note, it's good to see that you are keeping this car and going ahead with your build. You would have regret selling it, especially more so once it's back on the road.