Thanks Rocky- I think the 400s are really not an apples to apples as the 041 cam is much bigger than the 068 or 744. Those that have tried it in a street 400, especially lower compression know what it does. But even then the 5500 peak isn't a high rpm motor.
Even the D port 455s had a smaller 067 compared to the 068 with almost 15 degrees more seat duration and 9 degrees more overlap. So bigger cam and bigger ports and 10 HP more for only 400 more rpm in 71, 50 HP in 72. Interesting the big difference between 71 and 72 in HP when they made the switch from gross to net HP. Especially considering that the 70 455s with 64 heads had the same HP with the 067 or 068 cam-that doesn't make much sense to me, and only 10 HP less for the small valve 15 head 067 455.
The 73-74 SDs with the even bigger ports and a bigger cam(like the 744 28 degrees more intake duration and 22 degrees more overlap) picked up 50 HP.
So to make more HP based of a torque measurment the torque measurement must have been higher also.
OK some flow numbers same day we flowed these @ 10" multiply 1.67 for 28" numbers
#96 unported(identical numbers for an unported 6X-8)
0.1 47
0.2 81.6
0.3 100
0.4 110
0.5 113
0.6 115
197 unported
0.1 51
0.2 87.7
0.3 108
0.4 119
0.5 124.4
0.6 126.5
mildly ported 72 HOs-on a friends Formula now that was just in HPP
0.1 49
0.2 82.6
0.3 110.6
0.4 128.5
0.5 131.6
0.6 131.6
stock 614 flat valve-better low lift than tuliped higher lift the same
0.1 53.7
0.2 86
0.3 116
0.4 121
0.5 127
0.6 125.6
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