i was wondering, what the hell does this switch on the back of my FCON's GCC do...?

it's basically shows 4-6 and has a little switch....

 

Try calling HKS USA for tech support.

 

i called the local RX7 shop and they said it is a switch for 4cyl and 6cyl applications....

last time i checked the FCON was specifically for RX7's though....

 

The HKS FCON is not specifically for the Rx7, Its a piggy computer ( FCON V does fuel and timming ) for most japanese cars.

So your local shop might be right . But I personally dont know much about the FCON, just that a local skyline also uses it.