After I had already ordered parts, I found trick flow build a 446 with nearly the same size Hydraulic roller cam.
This is trick flows' dyno chart for the 446" engine with a similar sized hydraulic roller (243/247@0.050", 0.600"/0.600" lift, 108 LSA), shows 620 Hp at about 6,200 RPM?
I figure the larger engine will bring the peak HP rpm down a bit, but the wider LSA may extend the RPM?
They used 1-7/8" Hooker Super Comp headers, and open exhaust.
https://static.trickflow.com/global/images/chartsguides/t/tfs-k616-620-576.pdf