The 6G75 heads will lower your compression slightly as a forewarning.
But as far as making them work, all you will need to do is remove the cover where your distributor sits on the rear head. Make sure both engines are at TDC on cylinder 1 if you want to make your distributor install as easy as possible. Once you have that done, remove the distributor from your 6G72/74 head, as well as the studs, then install them both onto the 6G75 heads.
One other thing you can do, that isn't necessary, but would clean things up, would be to remove the cam sensor from the front head, and bolt in the cover from your 6G72/74 head.