The crankshaft small diameter register was changed to the larger diameter in 67. Small snout converters with high stall speed are impossible to buy off the shelf but you can have one built. I ended up putting a 340 crankshaft in my 273 with the larger register diameter. I then had the transmission rebuilt and installed the proper input shaft, pump, and clutch hub for the 67 and up 904. I could now use the larger register diameter torque converter. 65'
