I had the same thing. ;-) It supposed to be a torque/traction bar for a corvette supporting.
the differential during major acceleration:
The add:
"Corvette 1963-1979 Drag Race torque bars/traction bars . If you are taking your 1963 to 1979 Corvette with iron case to the Drag Strip (not recommended!) then these bars are the classic fix to remove stress from the diff nose bracket and prevent start line judder of the differential and bridge asembly.
In really horrible condition, these bars were removed from a 1964 on which we did a chassis restortion. They will need new bushes made, and one of the bars straightened. The front brackets must welded to the X-member, while the rear bracket bolts under the spring. "
Basically keep it straight during launch. It's a race rarity and I am going to put in on the Vette. It needs new bushings and I wonder where I can get them. May be the ty-rod bushings fit hmmm, I should check that.