It depends who tunes it, ive seen "tuners" that pick up little to nothing. On a stock truck, a good tuner will pick up 25+ WHP and 40+ WTQ. My truck is bolt ons and tune and is 485/526 NA, I never dynoed stock but we started around 460/480 before tuning. If Greg did your heads and it has a good camshaft grind and a good tuner, you should make at least 530/560, most likely more if they are getting everything out of the combo. You have some very vague details though: bigger valves, raised compression, custom cam, those dont really tell me anything. Whats the cam specs, true compression, details on the heads, etc. etc.
Justin