LS6 heads
#4
If I was buying a set of heads and was going aftermarket I would go with Trick Flow. I have stock LS6 heads (unported) on my car with my Futral F13 cam and the LS6 heads are worth swapping out. I see you have the MS3 cam and is and it is according to how much money you are wanting to spend. With the LS6 intake and MTI throttle body my car put down 427rwhp and 398rwtq on mustang dyno. I see you are wanting 425rwhp but with a automatic you are going to need aftermarket heads or ported LS6. Good Luck
#7