6-v8 Swap

I have a '65 Dart that was a 6 and I put in a 360. It took custom mounts for the motor and tranny. That was OK since its a bracket car. I p/u a another '65 w/a 6. I want to put a 273 in it and run it as a Stock Eliminator car. Do I need a V8 K member. I thought, although not sure, that the K member is the same for both. I also will need some solid motor mounts. Any good answers? Thanks