Yeah a switch from iron MW heads to aluminum heads should pick up some power. You might consider Trick Flow 270 heads rather than the Indy EZ heads since I think they will provide more flow for the $. You'll have to take a close look at what the compression ratio will be with the new heads since the chamber size will probably change. You'll also want to think about changing the camshaft since the newer heads have a lot more low lift flow. Typically you need to keep the cam on the smaller side with the Trick Flow heads or else you'll blow the power out the exhaust.