Honestly, it sounds about right. I would think a little more HP, nether here or there though....I just got back from dropping of my block at the grey's Automotive machine shop when the subject came up about the Trick Flow heads. He had just dynoed a set on a mild 408. Cam was a Comp hydraulic roller 230/236 @ .50, Eldelbrock air gap, and Holley Sniper EFI. Horsepower was 439, with torque of 470. He was disappointed in the numbers. His thought with those flow number he would see closer to 500 on each. They have also talked to a couple of other shops that have done similar builds, and they get comparable figures. Right now dyno sheets are being sent to Trick Flow to see if something can be done. The leading thought is that these heads may be too big for a street engine, but are waiting for Trick Flow to respond.
More cam and lift!
What header & exhaust tube?