If that engine came out of a 216 or a 316, it will have the extra mounting bosses on the block (my brother has his 216 torn down for refresh). These bosses are cast on the block and because the JD mounts the engine side-ways, the block won't fit in a Cub's chassis without modifying it. So even if you change cranks, there's that to deal with. My thoughts are to trade for the proper engine and save yourself a lot of frustration. Just my
FFGino. Happy Cubbing!!