Happy New Year back at you, Spook!
I'm not sure about that manifold for your combination in our heavy rides! It gives up a bunch below 5,000 rpm and gains it back @ 6,500 - 7,000. On the smaller engines it tends to be worse. It's designed for stroker combos or forced induction. I'd be looking at the FAST LSXRT or the Holley mid rise for better mid range and decent street manners.
Take Care,
Ken