340X heads
Since no one seems to be able to read your post properly, I will give you my best shot. You stated you HAVE "X" heads, so we should assume you are not a millionaire, and want to use them. I did this swap on a '72 Barracuda, and had great results. We shaved the heads enough to clean them up,added a comp cam(Extreme Energy),some cheap headers,stock 340 intake,and that was it. I saw a huge improvement in the car through the whole range. To make this work better,you will have to spend some bucks on a deeper cut of the heads(for compression,as stated),a good bowl job, and opening up the intake side of the chamber, and cylinder to improve flow past the valve.