engine questions, thinking about adding some bolt ons

I have a 1966 mustang coupe with a 289 engine, I just rebuilt the engine and put a weiand stealth intake, a edelbrock 650cfm carb, bigger valves in the heads, an elgen cam with .496 lift donno the rest of the specs because I lost the box. I also have headers, dual flowmaster exaust, march pulleys, and a hei distributor.

Well I was thinking about getting some AFR 185 heads for it, would they bolt right on or would I have to do something to the pistons, and im also going to upgrade the cam to a comp cams xtreme energy. here are the specs on that

Grind: 274
Lift: .519''/.523''
RPM Range: 1800-6000

I Also am going to add an edelbrock nitrous kit with a 100 shot.

Right now without the AFR heads, nitrous, and upgraded cam. The car makes 210hp and 230tq to the wheels. So Im wondering what kind of power the motor will make after puting those parts on the car, I was figureing about 175 hp more but correct me if im wrong. Please let me know asap.

On the afr website for those heads it says the max lift is .550 so wouldnt the cam be under that and not need to flycut the pistons? and how much would the afr heads help. Ive heard they get about 50-70hp more just bolting them on. So top that with a cam and nitrous and youve got a lot of horse power.

They are dished pistons and my motor rite now is at 9.5:1 compression with stock 289 heads, they said they had to put in dished pistons because my cam kept raising the compression.

So what do you think?