the 11" clutch is confusing
there are 2 belhousings & flywheels , the larger is 143 tooth , the smaller is 130 tooth
either can use the 23 or 18 spline disc as long as you spec the correct disc when ordering , the bolt pattern is different between the 143 & 130 tooth so the clutch is specific , both use the same 11" disc though
the b & rb engine use the same belhousing