Help Identifying K-members

The rusty K member is for a 70’-74’ E body and 70’ B body. Top set of lower control arms are 67-72 A body and the rusty set are 70’x74’ E body and 70’ B body. The spindles are disc brake spindles probably 73 up A body but can’t tell from the pic.

Thanks for the help. Is the K-Member small block or big block specific?