Thanks for the information. If I understand correctly then, the VIN number is not stamped by the factory on a 2008 3.6L Subaru engine. To make my reason for knowing more clear is my partners and I were sold such an engine specially modified modified as a "package" to be put on a homebuilt airplane (not an unusual thing in the world of built-it-yourself airplanes). We paid $30,000 for the engine. Yup, not cheap...and that didn't include the $9000 propeller. The man who sold it to us (who is still in business, but no longer selling Subaru engines) told us it was a new engine purchased through a USA Subaru dealer. For year he had bought Subaru engines, 2.5L and 3.0L, from Subaru in Japan as "test" engines which had been pulled off the production line for QC testing.
Unfortunately, we did not require the statement that the engine was new to be put on the bill of sale. The engine, complete with custom mount, 70 amp alternator, custom exhaust, custom radiators (too small), arrived, wrapped in plastic in a large crate on a truck about three years ago.
We put it in our 3-car garage awaiting the time we would hang it on the plane. About 6 months ago we pulled the intake manifold off as part of the installation process and to our dismay found water had been standing in the intake areas of all the cylinders, but especially cylinders #1 and #6. As a result, the stems of a number of the valves were rusted and pitted. Worried about the health of the inside of the engine, we hired an experienced local racing engine builder (however he was not especially a Subaru mechanic) to overhaul the engine for us.
Soon after he started he emailed us and said, "I thought you said this was a new engine. It isn't. It came from a salvage yard." So we all gathered in his very, very well equipped engine shop and he methodically showed us the wear on a number of items, indicating there was no way the engine had just factory test time on it, but he could not guess with accuracy how many miles it had on it.
I videoed his whole presentation. We paid him to put $2200 worth of parts in the engine and $1800 for his labor. He said several times, "I don't know how many miles this engine has on it because there is no VIN number I can research." And indeed, there is an area of the top of the bell crank housing just let of center near the starter hole that is obviously filed smooth where we guessed a VIN or other number could have been stamped. There was one number we could read: U234639.