Extra hp out of my 340.

Wow thanks AJ, might look at changing the gears to 3.55. Surely the extractors would help on their own. They say on average you get 10% more hp straight away. So that's 35hp, up to 375, only 25 more to go. Would changing back to the double pumper carby gain me some extra hp?
Below are 3 x pics. All I have on the motor was this cam card from when it was rebuilt in 2010. The other pic with basic stuff & the dyno sheet from when I bought the car.
I know the basics with how V8's work but my mechanical knowledge with lift & duration is limited. I was told the cam in my 340 is fairly mild.

Cam card 001.JPG

Cam card 002.JPG