I hope you don't mind me chiming in, but 4-5 ohms is high for this field resistance (but that is recalling off the top of my head); about 2-3 ohms is spec, I think. I won't be at my data 'til tomorrow night.
Bud, what do you mean by the VR 'burning up'? Are the wire-wound parts burning out? By the way, those are resistors, not fuses.
If the battery (-) cable was not well grounded, then yes, the voltage out of the alternator can be all over the map. Whether it for sure would burn up the VR is hard to gurantee, but I have indeed seen VR's burned out when people disconnected the battery (and so I tell folks to never do that). If there was another battery (-) connection to the frame (so that the starter could crank), than any and all starter current would flow through the engine-to-firewall wire; that would burn it up.