My neighbor uses Collectors Choice in his Jag XKE:
http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=65932
Lots of good info about it here, including why racing oil and diesel oil may not be optimal for your gasoline engine:
http://www.mossmotors.com/graphics/products/pdf/220-810_220-815_INST.pdf