I know skid plates exist on HEMI k -frames for B-bodies 68-71
there would be no such thing as a HEMI K frame after 73 for an A-body
This K-frame can be made to fit a BB but as I said in last post...(with modification). You would have to cut the perches off and relocate them for use with a BB, not terribly hard because even I have done it before but still some labor involved.
They did have BB spool mount K frames available from Direct Connection made to bolt a bb to without modification but this is not one.