What can I expect for HP out of this 408. Anyone else have something similar?

I ran that cam in my 318/390 - cast 587 heads flowed 243 @ .550...2.02 valve , soft in the exhaust.............so nothing great.

M1, 800 cfm carb,re-curved dist and Crane Hi-6.....and small tube tri Y headers....

My best MPH 111.2 in a 3650 car says around 420 HP.........that was dyno tuned then track tuned.

I reckon with good heads and good pipes you'll tip 460HP......