The sand cast aluminum COBRA POWERED BY FORD oil pans were sold as a factory installed option on new Cobras 1963-65 and as an accessory for any 260/289 Ford engine by Shelby American and Ford Motor Company concurrently to ‘production’ and for years thereafter. They were made in two different drawing revision levels. The original drawings had dimensional mistakes that created pans that did not fit the rear main bearing caps correctly. The drawings were changed and subsequent pans fit correctly. I have a photo copy of the original design drawings with the changes marked on it.
They were sand castings and they were hand trimmed and details polished so there was variation in most of the external features and details. Some pans look good from any direction. Some pans look pretty bad on the outside anywhere the as cast surface remains. Some pans have every ‘fin’ filled out completely while some might have an incompletely filled ‘fin’ somewhere.
I don’t recall anymore for sure date wise but some time maybe around 1979 I started seeing new made (aftermarket) pans for sale. The typical newly created pans were almost always cosmetically perfect on the outside. Since then other companies have made versions. Based only on what I have examined or owned myself the typical aftermarket pan is a heavier walled casting than the originals and most are not machined everywhere an 1963-65 ‘original’ was. I bought a car with an aftermarket pan on it and it leaked oil out of the side of the pan very badly. Once degreased wash water would run out of the side. The problem was very high porosity in that side. I found other people online that also had leaking through the walls aftermarket pans.
I put near mint used first version in our black car in the mid 1980s. It doesn’t weep oil out of its walls.