My doomed 408 build

IMHO unless you have your heads ported your engine will be done by 5800 or so.

I ran the older version of the cam you have, same duration but less lobe lift, with my 1.6 rockers it was .628/.633". It was in a 10.8-1 408, Curtis Bogs ported closed chamber Edelbrocks that flowed 293 with 2.02" valves. I had 2.055 intakes installed when they were freshened. It was running a port matched Victor 340 with a Bigs 950HP, 727 and 4.10 Dana. In my 3260# 69 Dart it ran 6.58 @ 104 and change in the 1/8 on pump 93 in race trim, in street trim it ran 6.70. It ran the same et shifting 6400 or 6600, after 6600 it started to fall off.

Hughes told me at the time I was running out of head.