NV: My memory may be playing me false, but as I recall adding a tach was pretty straightforward on the A series BSA's, so plenty of Thunderbolts and Royal Stars ended up with them. I serviced a few Royal Stars back in the day and always thought they were a very nice motorcycle. In fact I always preferred the Thunderbolts to any of the twin carb versions.
Flattraker: In my first year of dirt track I only qualified for two mains. Back then you had to time trial into the heat. From the heat you went to a semi, and from the semi to the main. At some tracks you had to win your heat just to make the semi. By about my third year I made most of the mains. At the end, after 42 years of racing I thought I was a lot faster than I was.
Oh yeah, never, ever worry about hijacking a thread, it's part and parcel of this forum and part of what makes it so much fun.