67 Cuda: disappointing dyno numbers, need some advice!

I don't recognize the number of that cam what are the specs
If you go roller rockers you need B3's kit factor that in I also do not see a gain with 1.5 maybe some with 1.6 on the intake
IDK about a 8 degree in/ex split with the late heads and headers
the new cam has a lot more lift so check the keeper to stem seal clearance
did you describe your exhaust? any restrictions will bleed off the top end
308s a great head for the HP you have may take major work to get to 400HP