What mounts are these?

Those are definitely 66-72 BCE bodies BB

To correct any confusion they will fit any 66-67 B and C body SB or BB V8 k member or subframe. Non hemi of course.

The drivers side has the tube welded in. It takes a long bolt there.

I can’t really PROVE IT (like Powerflite Wants) But I’ve been around for many decades and that’s like doing an ID on a Qtip. Very common part. But yes they have value with all the motorhome 440 swaps you need these mounts.