Without knowing the exact cam specs I don't think the results are far off from what the combo should make, it's probably closer to 375 at the flywheel, some fine tuning may net a small handful of HP but not a ton. The next thing I would upgrade would be some bigger valves and decent amount of porting in the heads (or sidewinder or edelbrocks) and at least a performer RPM intake as the regular performer is barely any better than stock. Heads or intake upgrade alone would not net much as the other would still be the choke point, doing both together should wake it up.