Are all 273 V8's the same?
Having seen this thread for the 1st time, it needs to be pointed out that the LA 273 switched to the larger crank pocket converter hub in '67, Slantys waited until '68.
Members CharrlieS, & more currently Slant Six, both had the reducing rings for putting '67&^ 273/'68&^ Slanty cranks on older small-hub converters.