I have stage VI heads on a 499 in a 3800 lb charger and with no tuning it has ran a best of 10.60 in the 8 passes I have on it. We will see how long they last I guess. I bought the whole top end package from somebody off ebay and they were already worked over but still brand new. I dont know how good of a job is done to them but they seem to make ok power. I think I have a little power left in it. I was launching very easy off a idle with the foot brakes. 1.52 60 ft. I guess I am happy with the power we will see on durability.