I have been looking at combines for a while now to replace the old TR70. A few guys around here told me since I've been mostly looking at 7720's make sure it's a Titan II and not just a pre '85 Turbo. What is the difference between the to series? I've tried searching for this in a few places with no luck so far. Just looking at them about all I can tell is the color of the lid and the return elevator. Any help is appreciated. Thanks.