I'm in the Blue Ridge Region, Southeast Division.
http://www.brr-scca.org/Ran many moons ago, 1978 with a then new, X1/9 Fiat.
Got back into it a couple of years ago with a 78 Fiat Spider,
the wife and I were rearended in the 78 and I hunted for
replacement and ended up with a 80 Fiat Spider, first year of FI.
In the stock class (HS) it would have been competitive if there were
some DOT legal autox tires to fit it, the 5 1/2" by 13" wheels were the
killer. Just changing wheel size automatically bumps it to CSP.
Since I was gonna be there anyway, CSP that is, I set the suppension
up and I'm running wider 13" wheels with khumo 710's.
Tires are the biggest improvement you can do, and to be competitive
around here you got to do it. ST classes are limited to street tires
with 200 or above treadwear. Probably the best tires out there
right now for that class are the Hankook ventus R-S2.
The 240z would be a great car to set up. Hope you get to run it.