Torque converter hub hole in the crank is to small if it has a 66 engine in it. 68 and up engines have the larger hub hole. There is a bushing to put a early trans behind a later engine but not the reverse
Correct.....a '68 and newer automatic won't fit the '67 and older crank unless you have a convertor built that has the features you need on both ends. If you're using the '68 engine and transmission as a unit, it will fit right in.