I too definitely recommend John. I think I was one of the first couple people from the CAC to have a conversion done by him. I went from the 85 to the 140. I was looking at doing the 165 unit, however there were two things that swayed me.
One was that the fonts between the tach and speedo were different. Or, they was a similiar font, but it just didn't look right with all the numbers crunched on the face.
Two, I had heard that the greater the range of these old mechanical speedos, the less accurate they are at given ranges. I don't recall if it's it's at the high or low speeds (or maybe both?).
Yeah, it would be nice to know how much above 140 I'm going, but I don't spend enough time there (*teardrop*) to warrant the 165 speedo. The 140 suits me fine. (I already know that I cap out around an honest 155mph.)
I also recall that any of the major vette places wanted like $300 or something and John was doing the same or better job for like $100. And anyways, the vette places usually send out there stuff to a third party anyways. I wouldn't be surprised if John is the one that does 'em, but due to contractual obligations, can't say that. I know that MidAmerica or Ecklers or whomever contracts out their steering wheel resto-service, so I figure they probably do it with other conversions as well.