If you’re interested, my parts guy matched my old one up with I believe a mount from 1970 thru 1972 Chevelle. It was the same height and bolted directly to the trans. The part was only $7.40 back in 1998. Also, if I remember correctly, I had to slightly enlarge the bolt holes in the crossmember and get larger diameter mounting bolts. Center to center was thew same. My receipt only has part #2378 but I don’t have the manufacturer.
If you want it exact, per Jim, re-vulcanizing is the way to go unless you can find an N.O.S. part.