Mystery radiator: ID help please?

[VintageMusclecar]

Had this in my stash for years, have no idea what it came out of other than the fact that it's a 4-row for an automatic trans application. There are no ID tags save for the one I'll post a pic of in a moment, and the only stamped letter on the radiator is the letter "K" on the top tank just above the tag. The upper mounting holes are ~27 1/4" apart, and the core is approx 25 3/4" wide.

I tried looking up the tag # online but came up empty-handed.

Any ideas?

Thanks.

Eric