You want to put all top layer traces on the bottom, and all bottom layer traces on the top? The first thing you'll want to do is create an intermediate layer to move everything to. An easy thing to do would be create a 9th inner layer to move to, then change it back to 8 at the end. Right click on a trace on the layer you want to flip first. Click find similar objects.  Use the find similar tool to select all tracks on the same layer.  Change the layer of those tracks to one of the unused inner layers.  Move the other tracks to the opposite layer, then move the tracks on the unused layer to the desired layer and change board back to an 8 layer design. Hopefully this is what you were wanting to do. For normal components just select the component and change its layer in the attributes.

hotkey T B or 

@cjohnson, @peternarbus, I've not looked at this particular project but be careful! * This procedure only works reliably if **everything** on the pcb is through hole. When you swap the tracks from the bottom layer to the top, the PCB Footprints for any **SMT devices** need to  be mirrored so their pads will no longer match the tracking. This may be OK for resistors, unpolarised capacitors and individual inductors but will be disastrous for polarised caps, diodes and most SMT devices with more than 2 pins.

@cjohnson That procedure worked perfectly.  Thank you!!

@peternarbus I'm glad I could help!