I know this is the IT web site, but I have a Nissan question concerning the engines allowed for the 84-89 Z31 in GT2...

Looking at the list of engines on page 262 of the 2007 GCR, I notice the obvious 2960cc V6 that comes stock with these cars. But I also notice other eligible engines include a 2899cc, and a 3498cc as class legal.

Does anyone know what these engines are?

In the engine type column it says:
V6
6 cyl
SOHC
DOHC

Could it be the "6 cyl" means the SOHC straight 6 in the 240/260/280? In the 240/260/280 GT2 car listing there is a 2899cc engine legal. Could the "DOHC" refer to the old IMSA GTP racer? If not, what would the 3498cc be out of?

It's winter; I needed a break from updating the roll cage; and I'm just thinking out loud...

Thanks,

Bob