I cannot tell you how much you would gain. Probably not much if you are keeping identical advertised and 0.050" numbers you have with the Scott Brown cam. A roller isn't going to move the valve much faster than that. Is the 0.200" duration above 165°?

Are you in an all out chase for the top spot relative to the "other" cast iron 4bbl intake BBMs in FAST and SC?

If so, I would probably suggest something like this order:
1) Make the intake the very best you can within your skill set/budget.
2) Install and go to the track and test with the cam you have now.
3) Then after establishing a solid baseline corrected to std conditions, then start changing testing and recording the results of the following for the cam you have now:
a) increase and decrease lash 0.004" on the intake.Keep going until it slows down
b) then do the same on the exhaust
c) then advance and retard the cam in 3° increments.
4) Read the tea leaves from the data and extrapolate your findings to spec youself a solid roller from what you've learned picking lobes that move the valve as fast as possible. Your valvetrain will hate you.

If you have not done this already, you might find a tenth or two and a mph or two with the cam you have.

Or call Dwyane and have a conversation.