The flow should be enough with your head work for more power.
IMO, the S&S cam is a bit too advanced, and there is a little bit of room to retard it 3 degrees for a 110°ATDC intake lobe center. I don't know the cam fixing sysytem, but if it uses the common Woodruff Key, you could get an offset Woodruff Key for the amount you need to retard.
That should shift the torque peak up to a slightly higher rpm, which might give it the hp bump you seek.
I know some people say that 4-valve can run shorter durations because of valve area, but I looked at those S&S cam specs which I presume are @.050" lift, and I find them to be closing too early for higher rpm power, with the flow that you measured on your ports.
Not a lot of room to shift that cam, but there is a little bit of room to go to 110 on the intake.
If you don't reach your power goal, you might try it.