mine was a '73 340 car before it was converted to a 440.
the builder (I bought it already done) used the Schumacher engine mounts (https://www.engine-swaps.com/). barring a few small cuts on the K frame to accommodate the oil pump, it was totally a bolt in affair. I highly recommend them
your '70 will be slightly different, but not by much. there are some pretty detailed instructions on their site with some great diagrams.