I am also looking for a wastegate and don't have a problem with aftermarket. It's bound to be newer than 1980. My question, as well as part # is, does it need to be a dual port? Is there a significant difference? And with the dual port do you have the plumbing diagram? It's the rear port that I question. Front port, (actuator side) to manifold, vac/pressure. Other port I have to a port on the upper part of the manifold, right under the carb.