That 315+ is way way more than I've gotten out of them. But, I'm usually going for the no-holes-no-tubes plan. I think low 280's is the best I've gotten out of a basic porting job, 2.055 valve. Those made 589hp on a 419.
This project was for a very good Friend that does my transmission work and it became a challenge project for me. They started out with me repairing a set of 400 dollar open chamber Edelbrock (340) style that I repaired then added a 2.05 valve. He was then curious how much we could get out of a 2.08 valve so I tried it. Without moving the pushrod I would NEVER do a set like this for anyone again, except for myself. A 2.05 is the way to go. He ended up never even using them and when he said he was going to sell them I bought them back because I had to much time in them to not have them. Being retired and not doing it for a living allows me to play around and I love flow testing and probing a port.
