the manifold nodes were worn, so i purchased a new carby manifold and it now sits on there really well, new o-rings for both sides of the manifold and a new ring under the starter housing.
STILL getting over-rev issues

Going to try a trick i saw on this forum while searching around, two washers inside the carby to lessen the throttle.
Otherwise, i might introduce the old carby to a sledgehammer and order a new one ^_^