Hi, I asked a question earlier about using GT40 heads on my engine. I accepted the answer. I have another question. 1989 5.0. ,19lb fuel injectors, roller rockers, E303 cam, 65mm throttle body, 70mm mass air meter, 1993 upper and lower cobra intake and plenum, is there aftermarket aluminum heads I can use with this setup? Really want to get rid of the cast iron heads.