Thought that this mught interest:
The last 4-cylinder motor built was # 5,069,697, with the highest LP motor under this number is # TR5,063,139, about two days production from the last ever. However, Hendon-assembled [LONDON] chassis number LP48228 registered in April 1929 had Engine # [TR]5,071,812, which is after the official “last motor”. To answer this conundrum Ken Kaufmann suggests that # 5,069,697 was the last DOMESTIC market 4-cylinder motor and export and service exchange motors were completed afterwards, including for Australia. It is suggested that 4-cylinder castings finished in mid-October, with assembly 2-3 weeks later, and then there was a break for re-tooling for the new 1929 6-cylinder motors, which were cast from around the first week in November onwards. Ken suggests that Saginaw cast a run of service Blocks and Heads right at the end of 4-cylinder production on the basis that it was a lot cheaper to run off several thousand components for stockpile rather than produce new castings at a later date. It is not yet known if any 4-cylinder castings were produced after 1928. It is likely that independent companies produced after-market castings as spare parts.
We know that castings were in fact produced and I think up until 1932 after which I seem to recall independent companies produced replacements. However I am open to correction here.
