Increase Head CC's
Measure the chamber volumes yourself, kits to do it are cheap and it's a simple process. I'd be surprised if they came out same as advertised. Usually it's a bit over because they have to account for tolerance in manufacturing and it's safer for the chambers to be larger than spec vs. smaller. Unless perhaps Trick Flow CNC machines the chambers too, which I doubt because that would add considerably to cost with minimal real benefit to the intended customer.