I was searching on the internet to see if I could find definitive information regarding ZDDP content in motor oils today. It would actually be nice to find out what the minimum ppm is really needed. It appears that Mobil 1 has some oils designed for flat tappet applications but very few other manufacturers actually list the ZDDP concentrations in their offerings.
I don't have a Speedster but the engine in my car is just like a Speedster engine. I have a 1972 Euro spec Super Beetle that was in storage in Germany/Bavaria for 38 years. It was purchased by an American serviceman in 2012 and from the few pictures he sent me, it appears to be during warm weather. It eventually came to the USA in 2015. I bought it from the second American owner in April 2019 a month before the car's 47th birthday. I have the original German registration booklet and it gives the "birthday", first day of registration and the original owners name and address as well as the registration done by the son.
The odometer/speedometer is in kilometers/ km-ph. The odometer now reads 53,040km. When I purchased it the odometer read 52,892km. If you do the conversion it is about 33,150 miles. There is a lot of evidence that the odometer is correct. The American that bought it in Germany did correspond with the original owner's son and he confirmed that the car wasn't driven after it was put in storage. The son also confirmed that he started the car occasionally and it generally started immediately without much cranking. I too noticed that after I purchased the car in that it was very easy to start even after sitting for a month or three. I did rebuild the front calipers due to sticking pads and squealing. I discovered that the front flexible brake hoses were the factory hoses dated 4-72. That was the month and year the car was built. I did replace the hoses as well as the hard pipes due to rust. I used copper-nickel DOM tubing.
With modern motor oils having less than half the zddp of oils in the 1970s and before I was looking for an answer to the oil I wanted to use to change the oil in my Super Beetle. It looks like I am going to use Mobil 1 15W-50. It contains a nominal phosphorus level of 1200 ppm and a nominal zinc level of 1300 ppm. The only Mobil 1 products that have higher amounts are the racing oils. I have order a case of 6 along with a half liter graduated pitcher that I will use to measure and fill the engine. The engine requires only 2.5 liters of oil.
What did the 356 Coupes use for a headliner? My car has a printed headliner instead of perforated vinyl-cloth.