I actually expected more out of the Trick Flow heads, even taking into account the cam and intake. I'd have guessed a 500h.p plus engine all day.
The heads are not holding it back from 500 hp. Brian at IMM built my 408 with out of the box trick flows and air gap manifold and got 506 hp and 506 tq on his dyno. Hydraulic roller cam of his specs but tame enough to run PB and A/C. Willingly gave up some hp for that.