milling 440source heads

Eds are off my 12 to 1 CR E body and I need to return them I dont want to mill them because then i wont have heads for my Challenger
Dart: I did not do my math when i selected pistons and my deck clearance is .100. With my darts 906 heads I have 8 to 1CR which is to low for my cam combo. I do not want to change pistons!!! 440Source heads are $1000 bucks,
Milling them to 68 cc's . How will this effect the quench????
Thanks-devil is in the details