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

I'd still like to see a photo of one. If true, they must have been in a manual transmission car, as all the automatic versions used a 727....which all used a big button converter. I have seen a few 340's with 273 cranks in them. Not from the factory though. They were put in because they couldn't find a good 340 or 318 forged crank at the time of the rebuild. One guy I know running a class drag car did it on purpose to lighten up the 340 reciprocating assembly. He also ran 273 rods, a 904, and a 7 1/4 rear for weigh savings!