V8 K member or engine mount adapters?

I was wondering if anyone has any input on installing a 340 into a Duster that was originally a 6cyl. Is it best to just get a v8 K member or use the adapter kits they sell? It may be one thing to get the engine in there, but is there a suspension difference at all if you adapt the 6cyl k member? I appreciate any input at all, thanks.