Planning for 408 - Possible Solid Flat Tappet cams

The split duration and wide lsa are doing me no favors. The TFS heads are good, but still too small for 400+ cubes and so trying to squeeze revs with the split and wider lsa is just dumb because the flow isn't there, I still only idle with 8" of vac and it stops pulling (butt dyno) just over 6k.

wonder if the hydro lifter is dictating your rpm capability, not the wide LSA and the heads.
if i had heads with a good flowing exhaust port, i'd run a singl epattern cam with wider LSA.