At a goal of 320HP with a stock healthy block-AFR 165's, Custom Cam (Ed Curtis mentioned above), 1.6 Roller Rockers, Change to new lifter's while you're in there, 24lb injectors, 77MM MAF (match injectors), 70MM Throttle Body.
Killercanary's combo comes to mind, he had the above mentioned and his dyno'd right there. Back in the day mine made 291HP / 312TQ with GT40X heads, Crower 15511 Cam, 1.7 rockers, Edelbrock Performer intake, 70MM Throttle Body, 77MM MAF with a best 13.26 at 107MPH in the 1/4 on street tires. I bolted a Vortech to this combo and it was nuts fast but never had it dynoed.