73 Road Runner k-frame

Have posted in FBBO but that place seems to be a ghost town so thought I'd try here. I'm looking for a k-frame for my 73 Road Runner. I was told 73-79 2 door b-body k-frame will work. It can be a small or big block k-frame I don't care. Must be in good shape I already have rusty junk don't need any more. Would prefer it be with in a few hours drive of Maryland, but will pay for shipping. Thanks Ken