1929 essex timing cover seal leak

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Hello to all. I have had a successful start up of total drive line rebuild of my 29 Essex coupe and addressed all oil leaks except for the timing cover seal which I cannot seem to fix. I fitted a new felt seal which leaked and so I removed the cover and refitted the old one which leaked and had it off a third time fiddled and worked the felt and refitted it and it still leaked. This is stopping from moving forward and I am stuck...!!

I would dearly love to fit a modern seal into the cove but the design of the cover means that this would be very difficult.  Has this been done? Any ideas would be greatly appreciated...

Regards. Mike.