You've put a fabbed aluminum pan on one of these L6's? Where did you get it?
I don't have the pan anymore and didn't originally order it, but If I recall correctly, it was from Stef's (
http://www.stefsperformance.net/).
The Chevy L6 isn't listed in their catalog, but like most things with Inlines, it would have been a custom order.
I think any of the oil pan fabricators would be able to build you a pan. Just be prepared to spend some $$ and wait awhile.