I'm planning on doing a small bumper conversion on my 73 comet GT. Does this mean I would need a front valence and rock guard from a 70-72 or would a 73 valence and rock guard work? My 73 valence is messed up so I have to buy one either way. Also are there any mounting differences between these valences that could pose a challenge? And I would greatly appreciate if someone could put in a link to a place where I could buy the required valence and rock guard for the conversion. Thanks.