You just need to do a little research on you eng before you jump of the wrong cliff.
You need to know the lift of your cam, then x1.5 that will give you your valve lift........
If you have a lot of lift and you shave your heads down..........the valves get closer to the piston.......if they are close now it might hit afterward. bent valve = no compression in that cyl.
If you have a small cam, say .430 lift and alu aftermarket head will not give you much bang for the buck.....but a .450 to .480 lift cam may wake it right up.
OK ok lets start from the TOP!
What gear ratio do you have?????????
Do you have a tachometer??????
What rpm does you combo stall at now. aka left foot on the brake as hard as you can and mash the skinny pedal with your right, to the floor. look at tach........what rpm did it go too???????
What intake manifold do you have on it right now?????
exhaust manifold or headers??????
Answer all of these and we have a start of spending all of "your" money in the right direction.................