On E bodies the rear frame rails swell up and rust
thru where the rear shackle is mounted. This is a seperate piece that slips into the frame rail and has the bumper mount holes and shackle tube built into it. Is this part available from anyone or just as part of the reproduction frame rails?
I don't need frame rails,just the part that inserts at the very rear. Thanks

I would like to know this as well .

I havn't seen just that piece available. I bought the rear frame rail sections for my car. They are around 27" long I think. You could always get those and use what you needed but they aren't cheap. You'd be throwing away most of it.