Thanks so much! The closest match to what I believe to be correct is the 80 mph speedometer in your book, as I believe the Pontiac AC Speedometer for 1926 was like that except the maximum speed is 75 mph. However, I have seen a few in 1926 -1927 Pontiacs that have 80 mph on them like the one in your book. At any rate the reset stem is at the 5:00 position coming out of the base instead of coming out of the face of the speedometer, as it would not fit in the hole on the dash unless it coming out of the base. To sum it up, I think the correct model for the 1926 Pontiac is a 75 mph version of what is shown in your book.
Where are you located?
Thanks!