I wish there was a simple answer to this but there is not. Classification is based on a point system similar to, but not the same as, that used by AROC National (
www.aroc-usa.org). I believe you can download the AROC Competition Code from their website. Basically, class A through F cars are production Alfas of one sort or another. Class Z is a nonproduction vehicle (formula or sports/racer) using Alfa power with >1300 cc's. Each Alfa model is given a point value based on it's preceived competitive potential. After that, points are added (subtracted?) based on modifications that alter that potential. For example, a 1600 GTZ is given 186 base points while a 1600 Giulia TI is 125 base points. Changing to hotter cams adds points. The number of points depends on how "hot" the cams are. Going to race tires adds points as does changing the size of the wheels and/or tires. You get the idea. All the points are totaled and the final value determines the classification.
Basically, an A class car is a very race oriented car, lots of mods. An F class car is a very street oriented car with relatively little speed potential. Oh, there are actually G through J classes but I've never seen one at the track. There is also an X class for non-production Alfa powered cars with <1300 cc's.
I hope this helps. If you want more detail, the best bet would be to contact the Competition Chairman at AROSC (
www.arosc.org).
Finally, I appologize for spelling Derk Stoher's name incorrectly.
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Bruce Colby
Competition Director, AROSC
'65 Sprint GT (TS race)
'69 1750 GTV (TS street)
'71 Jr. Z (special occasions)
'89 E30 (the dark side)
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'69 1750 Spider (sold

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