I had the same problem, take your old transmission mount to O'Reillys and ask them for the Pioneer motor mount/transmission mount book. There are pictures of every mount twords the back of the book, thats the only way I was able to find one! Good Luck, Ill look and see if I can get that part number again when I go to work today!
1969 Chevelle...turbo 5.3
1994 Impala SS
2008 2500HD Duramax....RCSB conversion
1954 Chevy truck...Duramax swap
2015 Z28 #125