Well, there were a couple of big time American builders back in the day: Tesch, Eisentraut, and Cuevas. You are certainly buying a piece of history. I suppose this isn't John Howard's bike, but a model named after him.
It will probably weigh 21 lbs, and not ride as well as current steel bikes.
Being part of that era, I lack sentimentality about bikes like these. I think bikes today are better performing. But if you are into vintage, it looks like a good deal.
I looked at the picture again, and it seems OK for a head tube length. 55cm TT (21.65 inches) seems a little short for me, and I am 5'11" with average arm length. But you could compensate with a longer stem.
The bike has americanized "crit" geometry. People were nuts for bikes like that then, 1/3 TT bike (short TT and HT), 1/3 track bike (steep st angle, ht angle, higher bb) 1/3 road bike (gears and brakes mostly).
John gave me one of those he had laying around as my first nice road bike back in about '94, I rode OK, but was a little stiff for my tastes. An ENO hub would make one a pretty fun points-race bike though....