[ted]

Top speeds vary at the different So Cal tracks.
So you might have to compromise and gear the top mph for Cal Speedway.
The top speed at Big Willow and Cal Speedway could be 10 to 20 mph faster than Chuckwalla and Buttonwillow.

If you are going to buy new I'd try Patrick's 70mph 1st gear for those slower starts when you might drop it into first to keep it in the power band.
Then just space the gear stack from 70 to 145?

My non porsche V8 race car has a quick change (weismann 5spd).
We gear for 145mph top speed at Coronado, Monterey, Sonoma, Buttonwillow and Chuckwalla.
165mph for Big Willow and even a little higher mph for Cal Speedway.