Head flow for autocross torque

[SRD Art]

My current SBC 406 has roughly 325 ponies and about 400 ft lbs. It runs a stock bottom end with 8.5:1 dished pistons, an XE268 cam, and self ported factory 400 "low performance" smogger heads. This motor is approaching the 100,000 mile mark and although it runs great I am after more power and a beefier bottom end.

I already have a fresh flat top pistoned short block 406 rebuilt and ready to go and was curious how my research compares to you all. The goal is approach 1 hp per cube and 500+ ft lbs to move my 3600 lb wagon around the autocross at a decent speed. I have been looking at bigger cams and budget head options and and like the Vortecs but rebuilding a junkyard set wouldn't save that much over a set of say Summit heads which are $700/pr.

The summit heads are 165 cc intake ports. Obviously small ports create velocity and = torque but 165 sounds really small. Most of my experience in the past has been drag racing and starting with a 200cc runner and porting from there. Those motors also launched at 4500, had a torque peak at 5000 and I shifted at 6500. I want to keep the power band low, like 2500-5500 and hopefully torque will be flat and peak around 3500-4000.

In your experience can a small 165cc port head handle the power goals I'm after?

Anybody know who mfgs Summit's heads? Thanks for insight!