How much power increase?

The first engine in my hot rod project will be a stock CSB from a '92 Caprice. This engine is rated to 190hp in the Caprice.

However, I will do some changes to make it breathe better and to minimize the loss of power:

-Full length headers, 2,5" dual exhaust w/crossover pipe, flowmaster (or similar) mufflers.
-Remove the PS and AC. (The car is a 34 Roadster)
-6 speed manual T56 transmission.
-Use electric cooling fan instead of the belt driven one.
-Air gap intake with 625 cfm Demon carb + Pertronix HEI distributor.
-LARGE high flow K&N airfilter in combination with some sort of cowl induction system.

Will these changes actually make a noticeable power increase?
If we stick to horsepower, how much (approximately) do you think it will increase?
What'll bee the next step for such an engine? Any advices?
Vortec heads and a different cam?
In that case, how much hp do we talk about then?