Do I Need a Bushing for the TC for a 273/318 Swap?

All 318's I've ever seen have the large register for the torque converter. As far as I know, only the car '64-7 273's, and the '60-67 slant 6's were the only engines with a crank with the small register.


I’ve actually physically seen two 340 cranks with the small register. I’d never seen one before about a year ago.