I did a fair amount of them when I worked at the Dodge dealer for 24 years. We had replaced a few heads under the powertrain warranty when valve seats came loose. Also would see some engines all sludged up real bad and of course they all said they changed their oil every 3000 miles as we recommended on that eng. But when replacing the chains it was nice to have the tool that holds all three chains in place on the idler gear in the block which is where the cam gear would normally be in a pushrod eng. We had the special tool in the tool kit the dealer gets for the 4.7 eng. I left the dealer in 2011 so its been a good 6 or more years since I replaced them but that one tool sticks in my mind as making the job easier. Maybe one of the guys who has done them lately will chime in on where they get the tool to hold the chains in place on the idler gear on what some call the dummy shaft. Ron