Clois is right. That is a huge leak for a rear main. Do you have an inspection plate on the bottom of your scattershield? If so, remove it and look inside. If the leak is from the rear main, it will be wet in there. If just the outside is wet, then it is most likely leaking from another source. Also check the rear gasket of the intake and be sure it hasn't given up and let
oil run down from there.
Ron