[289ACE]

That was the letter I also saw and was referring to, but I think that particular Ace ceased to exist and became a Devin at some point, or maybe just a backyard special that has disappeared. Another interesting thing I found about the car; when I was searching for history on the car, I called Ak's garage that is still open in Whittier, Cal. I talked with one of the guys who worked with Ak back in the '60s, (Jack Lufkin) and he said Ak had a V8 in that Ace well before Shelby was doing it. He was not sure of the exact time frame but was sure Ak had beaten Shelby to the punch.
Edit- Tom, just saw your post after making mine. I'll look for my copy of the letter (mine was a copy of a copy) but if Rick has one it will probably be a better copy.
Jay