Get a manual trans flywheel from the same vintage as your engine. 283, 307, 305, 327, 350 all used a flywheel with no external balance weight. There whould be 350 flywheels around, lots of Camaros had Super T10's in them back then.
Check the installed height: crank surface to clutch surface. Then check the installed height for the T56 flywheel. Use care, this should be done with a depth micrometer or digital height gauge.
Make sure that the early flywheel height matches the late one.
The rest should work. Double check the pressure plate mounting holes on the flywheel.