While visiting George at MGW I received a text from my good friend Tom Wenstrom. Tom serves on Dean Martin's crew at Rehagen Racing and just happened to be there when an opportunity arose - to accurately measure the weight of a typical S197 axle assembly (including the UCA/LCA's, etc) as well as that of a '15 assembly with an iron center section.
Tom said:About 110# difference. Not too shabby, and the un-sprung weight difference should be pretty significant as well but we didn't get into tearing apart the IRS as it will be getting bolted into the new race car in the near future hopefully.