I think that depends on how you define "left side frame rail". From the countershaft sprocket to just before the rear axle assembly, a newer Hench meets the letter of the rule; but I could see where an over-zealous official might look at the "jog" that moves the rail inboard of the sprocket and interpret it as not being "within the frame rail". I'm sure that the intent of such a rule is to further limit radical engine offsets but such questions point out just how difficult rules creation and interpretation can be...