I think the 3600 used an Eaton HO52 and the 3800 used an Eaton HO72.
The difference is at the outer ends. Larger backing plates and
brakes. As far as the mounting pads, someone else will have to
help you, my guess would be that they might be different.

Best I can offer is that the spring pads on my '50 3600
are 41.75" on center.

dg

Last edited by Denny Graham; 09/16/2014 1:05 PM.
Denny G
Sandwich, IL