Breathing life into this half dead horse I can say no, Dana 70HD brake componenets do not fit on a Dana 80.
The spindle on the Dana 80 has 1/4" less distance from the rear axle flange to the inner wheel bearing race. The Dana 70HD inner wheel bearings are the same as the Dana 80 but the outer wheel bearings and outer spindle are a smaller diameter on the 70HD. If you try to space out a 70HD hub on a Dana 80 by using a 1/4" spacer the sealing service is not in the correct location.
Needless to say after many phone calls to axle guru's my 70 is staying a 70hd and my 80 is staying a 80, no hybrids.
Ryan
