On a V8, the pulley bolts onto the damper, On sixes, the pulley IS the damper. So, no they aren't really interchangeable.
It is possible to make the V8 damper work, but you will need to monkey with everything else to get it all to line up correctly. Much easier in the long run to get the right part...
There are several places that specialize in rebuilding dampers. I believe most generic parts stores can get you a new one also.
