t5 trans swap?

well providing you have a steel crank 340, some 1973 340 motors were cast,,a steeel crank fly wheel from a 340 or a 318 will work,,a 273 fly wheel is to small,,dont get a fly wheel from a modern 5.2 ( 318 ) or a 5.9 ( 360 ) they are balanced differently,,,

try to find a used factory 318/340/383 fly wheel make sure its for a 10 1/2 inch clutch,some 380 had 10 1/2 im not sure if any 440 came with a 10 1/2

look on moparts.com or buy a new one from mancini,brewers, maybe summit or jegs,,just get the quick time before they are gone,,, good luck keep us posted on your conversion