Changing to a larger duration and lift cam is not going to fix your hesitation issues. It will allow the car to utilize your heads more to their potential. If the hesitation is your only issue, my question is has someone REALLY tuned your car? Maybe you should do that before spending money and time on a cam. If it is still not what you want, then get a cam.

 

i'd check on ignition first before changing the cam.
I mean if your car was running better before you got the aluminum heads and the old heads were stock, then i don't see how that could be the cam.