what you will be doing is a top end overhaul.. includes head rework. new valves , valve seats and seals. new rockers if needed. new valve guides.
pistons rings will also be changed... while pistons are out see the condition of the cylinders. if the honing marks are worn out the cylinder will have to be rehoned. if too much rehoning is needed than you will need new pistons.
any how a top end would set you back around 15k..