Think you'll find pure alloy would be a little too soft for the sort of abuse a gear lever gets, and as castings go, the Jap stuff ain't too bad.
Classic bodge though, and one I've had to resort to in the past.
Always helps if you know any nice friendly engineers who can repair it for you!!
Have you tried looking on ebay for a replacement lever... may save you a few quid! (couldn't find anything on there at the mo though

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