another cooling tin question

[Carlson Bryan J <bjc159s@nic.smsu.edu>]

Sorry about this folks, but I have another question regarding cooling tin.
Upon installing my oil cooler, I realized that there should be a piece of
tin between the cooler and cylinders 3 and 4.  This is obviously one of
the infamous oversights in the Tom Wilson book, as this piece is mentioned
in the Muir book.  The problem is that my engine was lacking this piece
when I purchased it.  Could anyone describe this piece to me and give
me some odds on finding a piece such as this in a junkyard somewhere?
Thanks,
Bryan
73 sq