All 340 rods were floating. They just installed the bronze bushing for the 340, which ever rod the were using. Earlier 340's did use a different forging, 495 sound right without looking. Most 72 and 73 340's I rebuilt were using the 645 forging. I've never seen a light duty rod in a 360. We used to get 360's for the heavy rods for use in 273's and 318's.
