Sorry to bring up an old post, but I have some half decent pictures...
1.5" 'Z' is all you will need. It's actually 1 5/16" but 1.5" is a safe bet. You can actually get away with not 'Z'ing the frame. You can cut the bottom off of the crossmember, and rebuild it. Your front rails end up being about 1/4" off the ground right before the bend up. This is what I am going to do. Even thinking about moving both arms up about 1/2" or so, and dropping the motor 1/2" to 3/4" to keep the stock hood.