Agree with techinspector1...I would do the same thing with them, but in my opinion, it's a waste of money and time to do the bigger valves and port work. Use them as they are, fine. The port work and flow increase will only show your efforts when you see maybe 6k rpm, and you wont see that with these heads. And as far as out performing the large oval ports, no way...They would be quick out of the hole, but would run out of gas really quickly, where the others will keep pulling. Thats why they used them on trucks! Lots of power, but low rpms. They're just not a performance head, no matter what you do to them. But for a tow truck or stump puller, great!!