Head upgrade. Cnc, big mouth, or different heads ?

So my engine has some issues do to gas getting in oil. So since I have to tear it down I'm thinking it's a good time to try to grab some extra ponies. I'm in no hurry cause summer is over in about 6 weeks here so my season is done. My combo is 416, 10.7:1, hydraulic roller (240ish duration and 550 lift ),forged pistons, steel crank and ported eddies. I know this isn't a question than can be answered with a straight answer but what could I do to get some more power out of this thing and still stay streetable on pump gas.