I also have those heads on my Hemi with no problems. Those heads were made for weight loss which if I remember is around 50#s a head. When going from iron to aluminum heads you'll need to increase the compression because it'll lose compression due to heat loss.
I guess I'm not sure if it really loses compression or it just loses power due to the heat loss???? But if you just change heads the engine will be a little down on power if they flow the same. Aluminum plus 1.
On the weight the original cast heads were a little over 60 but the mopar cast replacements were around 20#s heavier. The aluminum weigh a little over 30. So weight savings depends on which cast heads you have.
