Welcome to the forum!
I'm not an engine builder but I'll toss in a couple of thoughts to give others something to yell at. If you're experienced with porting you might gain a few HP by smoothing the flow path, but if that was the only thing done you won't feel the difference in the seat of your pants. Repeated, consistent runs down the strip maybe a very slight change in your time slip, but not big changes. I've seen some articles showing that a little bit of mismatch on ports actually causes better mixing, especially at low to mid-range rpm's, and that at peak flow the pattern actually smooths over the small step - talking less than 3/32" step, not all the way around. Case in point, looking at the exhaust side the guys at Hot Rod did a series of dyno runs, starting with a new set of tube headers as a baseline, then started beating on the tubes with a hammer with dyno runs between rounds and found that they actually GAINED a HP or two on some runs. I'd say fix any big port mismatch, and you'll get more from the right cam selection than porting.

Now let the guys who really know the facts start telling you how everything I've told you is HogWash! And Woooooooooooo PIGS!!