You won't have the benefit of the APV valves which basically means it's a 4 port with 6 port irons . The port timing on 6 port irons is inferior to the 4 port if you aren't using the apv. Ad to this that the two middle rotors have inferior intake runners as well as inferior exhaust ports and you have an engine that will offer less power than 2x 4 port engines. I think you will struggle to break 300whp.
I think your best bet to do better is to port the exhaust ports as much as possible and bridgeport it .

 

The plan was to port the irons as much as I could to over come this but this would always have been a proble as i wasnt going PP. I know that the apv won't be used as I'll probably be doing something along the lines of independent throttle bodies.