vacuser
Dwayne,
All Heritage model 1-HDs (Heritage 84 also) had the narrow 4.5" long axle as the only Em-Tor they had was large.
Beginning with the Heritage II model 2-HD, the Mini Em-Tor was used on most models and thus had the newer, 6" long rear axle; however, those Heritage IIs with the shake-out bag also had the large Em-Tor and thus the shorter 4.5" rear axle.
The Legend II was the last machine to have the shake-out bag option.
~Ben