I believe that there are only 3 K-frames for an E-body.
- 6cyl/small block
- Big block
- Hemi/Six-pack

The only difference between the k-frames on a hemi/six-pack car and the regular big block k-frame is that the hemi's and six-pack got a skid plate (to protect the oil pan) and a small metal "coin" welded onto the front edge, driver's side.

Bottom line is start with a big block k-frame. You can buy the skid plate (reproduced) and make a fake "coin" pretty easily (if you're trying to look original). B-body & E-body k-frames are the same.