Howie... the 1.60 is the pivot length of the rocker like Brent said, not the ratio. The Blue Thunder for the FE is the same pivot length 1.60. These are "race rockers, and are available in many ratios, with 1.75 being standard, but 1.8 or 1.85 or even up to 2.0 available if desired. The Blue Thunder "THOR" head is a BBF or 385 series head, not FE, and the 1.65 or 1.75 as a custom is again... pivot length not ratio.
T&D make the rockers to order, so you can get any ratio and many offsets if desired, within reason. I have handled a few sets of T&D race rockers for both Blue Thunder and Edelbrocks, have them on my own engine, but never a "street" rocker assembly... so no idea on that stuff, yet. I'll admit the T&D catalog reads a little funny, but you didn't understand it correctly.