Dan, your car was built in july of "66"*
In order to help with actual stats for the ZF's box's, Dan can you check your metal ZF tag, it should have (032) hand stamped in the top right hand corner. Then in the bottom right corner, your box will be hand stamped with a "number produced" around (350), that's my guess.**
Garry, since yours is an actual carded ZF S 5-20, Can you check your tag. It should be (064) and "number produced" around (135)
*/** This is info I got from our Tech. Manual, Production Stats, and the reprint from ZF's Production Data for All transmissions built for DB cars. Lets see how acurate the printed info is compaired to our cars.
Thanks
rocketman1