original engine numbers

[my1973911S]

Can anyone let me know how I could find out what the original engine number at time of manufacture would be for early 70's model 911 by reference to the chassis number on the car?

[ossiblue]

My understanding of the general rule is this, using the 1973 911S in your screen name as an example:

Your VIN would be 91133XXXX, with the fourth digit (3) indicating the year and the fifth digit (3) indicating the car is an S model.

Your engine number should be 633XXXX, with the second digit (3) indicating an S motor and the third digit (3) indicating the model year of car it goes in. In short, the fourth digit of the VIN should match the third digit of the engine # and the fifth digit of the VIN should match the second number of the engine #.

If you want to know if the motor in your car is the one that was installed in the factory, I believe that can only be determined by a COA. Having matching numbers, as indicated, shows the proper engine for the proper year and model of car, not necessarily the exact engine that came with the car.

You can follow the general rule, above, and substitute different model years for the fourth digit--0 for 1970, 1 for 71, etc., and the model type (fifth digit) will be a 1 for a "T", 2 for an "E, although I have seen a 5 in this location which was for a ROW "T". In the engine #, not only will the third digit (year) change, but the second digit may also--1 being a "T", 2 an "E.

Hope this helps. Others who are more expert will add refinements

[my1973911S]

I have heard that some Porsche parts dealers have computerised records and by entering a vin number they can tell you the engine number and all the specs the car come with out of the factory. Is this correct?

[ossiblue]

I've not heard of that claim but I suspect it could be true of new Porsches. Given the posts I've read about getting COAs for older cars, such as yours, I doubt there is a computer base with that information available to parts dealers that would apply to cars that are 30-40 years old. If someone can confirm that there is, I'll believe it.