port and polish

i have heard a lot of stories of how getting my cylinders ported and polished could be very good for a HP gain... whats a safe amount to bore it out and how much would it cost?

P&P involves the head, not the cylinders. If you wanted to bore out the cylinders on the KA then it's possible, but only to a small extent. The walls on the KA are already somewhat thin and can't be bored much. JE pistons does make pistons that are .020 over and a good amount of people do that for the KA. Porting and Polishing involves the head and it's possible to do that as well. Ferrea makes 1mm oversized valves for the KA.