[NHVANA]

Rowan,

The factory Superformance headers are restrictive (even the new sets) they have a real tight turn at the rear that will not allow the BB to breath at full noise. Because the 385 is so large it will be real tight to modify these without attacking the heat sheilds. Rework your headers and it will be a whole new engine.
Check your port matching on those Kaase heads I'm picking that will be out also.
After that, start with your internals.

My previous engine set up had roller lifters and a wilder cam profile, that engine would ring like a bell and frighten my wife and any other willing victim. However, with that came unreliability (firstly a broken rocker post and then a collapsed HIPO lifter after 1500miles) money was burned.
Finally, I'm suggesting that you get the huff and puff right you may find that will satisfy you for a while, then move on from there.

Give me a call some time, lets catch up for a beer at Puhoi on the next fine weekend.