The 67 and earlier Slants have a smaller crank register. 68 up are larger. Thus a newer 904, like yours the torque converter has a larger "snout" and won't fit into the earlier crank. Now the crank may have been machined to fit the newer converter, OR a custom converter was made. I mated a 71 904 to a 67 crank by having Hughes transmissions make a converter with the smaller snout. The front pumps are different along with the input shaft starting in 68 for the 904 transmissions both in the Slant and the V8.
