port advice

i have a wedge box 30 wide 19 high 9 bd 6 td , with a slot port facing the drivers side of a 1996 reg cab s10 , my problem is i have amps behind the drivers seat and dont think im getting enough airflow , im running a re sxx and think i could do better on air flow but dont want to build another box , i was going to cap off the port and use a round port on the top , my question is , do i need to remove the old tuning port ?? thanks jim

No, the old port can remain in the box.  It won't function as a resonator if it is sealed.  I've done this before myself.Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.