Unfortunately no, the 8.1 has an Oil Pan all it's own-the GM Part # is 12587863-looks like it's still available:

Genuine GM PAN (12587863)

That Pan fits a 2500 Series Truck, so I don't know if it will fit your application-

As far as a custom Pan, Stef's (and B & B which is a part of Stef's) both offer a Pan for the 8.1, or will custom build one to your specifications:

Oil Pans - Stef's Fabrication Specialties And B&B Performance

hope this helps-