Please correct me if I am wrong, but this is what I believe is the case for ALL Sunbeam Tigers (Mark 1, 1A, 2):
The casting numbers and the dates they indicate can identify if the engine COULD be the original for the car. The key word: "could." Obviously, an engine produced after the car was built could not be the original. However... Ford did not stamp specific VIN type numbers on any of the early 260's or 289's... but they did start doing that with Hipo 271HP engines. That is why (say with a Hipo 289 Mustang or Fairlane) there is a way to establish if the engine was the original.
But, with all Tigers (correct me if I am wrong, please)... a specific engine can only be established as a "date of build" appropriate engine... but there is NO way (emphasis on NO) that a specific engine can be 100% identified as an original in a Tiger. An engine can be identified as "NOT" the original with 100% accuracy (e.g if build date is wrong or it is a 302 or whatever). But... if anyone claims that they know with 100% certainty that the engine in a specific Tiger is the original... it had better be the original owner who is making that claim. Fact is:
no ID on a specific engine can be tied to a specific Tiger. So, even if it is the original owner making the claim... it is his word you are trusting, not something that can be independently verified.
So... am I blowing smoke (Norm... or others) or is this really the case?
Bill