GT40P heads have great flow characteristics and you can probably pick up a pair for half the price of after market 'racing' heads. Look around at swap meets, someone will have an old pair that need refurbishing. You will need JBA 1650S-2 headers to clear spark plugs. What rear gear ratio do you have? That is important. I've heard guys complain about how much they have put into the engine and it's a 'dog'. They are still running the 270 rear. Should go at least 355 or 377. You'll be surprised how much difference that can make.