Replacement Engine Case
 

To finish up a point from another thread...

If you are going to replace an engine case with an engine case with no serial number ( a blank case), you can stamp it with the original engine serial number. But, you should prepend "AT" to the engine serial number.

See this thread:

Porsche356registry.org - Engine S/n

To quote a poster:

"AT probably means "Austausch" ( German for replacement )"

This is the only ethical thing to do. Especially on a car where having an original engine would affect the value of the car.

Scott

Any code affixed in the OEM position on the blank case should be done by the manufacturer (Porsche)/authorized dealer... if Porsche uses AT or KD to mark the replacement case in their inventory records then if parties not authorized to place the mark begin doing so the records may not line up. If you need a replacement case and want to have a marked case including the original number then Porsche or an authorized Porsche representative will need to do this if you want it to be 100% legit.

Joe Schmoe Speedshop shouldn't be renumbering or coding engine cases to appear as though Porsche did the work even if we've deciphered their replacement coding methods.

Adding the KD or AT is a step in the correct ethical direction and is reflected in Porsche practices but one would still signing their work for them.