Ok, first, I am more interested in seeing the numbers at the track than what the dyno had to say. A dynos accuracy is almost always questionable.
That being said, I previously mentioned that I hoped it would make 620. It made 631hp at 6800, and 563tq at 5100. This is with the heads as is, right out of the box, other than a spring change to better suit the camshaft.
I am anxious to see the track numbers, because the dyno operator insists the dyno is 4 to 4.5 percent low compared to before a software update that reduced the numbers. I will not make that claim, but if the track numbers support it, then that's what it is.
The takeaway is that obviously the port works very well, especially with a 2.02" valve, but lacks the cross sectional area to carry the torque curve with a 416" motor. That will limit high rpm horsepower, but makes for a broad torque curve in the mid range, which is what you want from a street/strip engine. Overall, I'm very happy with the performance considering what these heads were asked to do. We could have gotten a little more compression by nipping the heads a bit, but the goal as to test the heads as manufactured.
I still say this is the best bang for the buck head that uses a standard valvetrain. Sure you can buy another head for less money, but to bring it up to this level of quality and performance, it will cost far more. Period! You may be able to port heads yourself, but unless you are willing to do it for others for free, you have to consider the value of your time. If you are willing to do them for free, PM me your address so I can send all of my cheaper heads to you and save hundreds of dollars.....except I won't. I still have to replace all the hardware, guides, seats, etc. that will cost me more time and money. Its a hard sell to say you can get by cheaper with a lesser head.
