I received a rear valance from AMD for a 70-71 challenger and it has no welded brace behind the license plate as my OEM non R/T car has and i have seen on OEM R/T units.
Speaking to a rep from AMD, he stated some cars had the brace and some did not so the left it off.

Does anyone know which cars received it and why?

I don't see how this thing is not going to flop around without it. The 2 bolt on brackets do not seem enough.

That center bkt. replaced the other 2 bkts. from 72 on. Maybe late 71. Just another 'improvement' chrysler made after initial years. But you can use both types if you desire. Interesting: if you had ordered one for a 73, would it also come with no bkt whatsoever.

bracket puts the licenese plate out further on the energy adsorbing bumper cars 73-74

Can you post pictures of the bracket or area you are talking about?

70 and 71 are two totally different valences

The bracket pictured was only used in 73-74. Since the bumpers were moved out farther way from the body, the license plate light didn't aluminate the plate any more. That bracket was needed to move the plate out to the light source.

Speaking of Challenger rear valances, is this one 72/74 style?

That style center mounting bracket was used in 71-74. If there is no license plate bracket welded to the other side, it could be a 71 or 72.

yep

There is not a bracket. 71-72 then. Thanks.

The 70 will have none of the three brackets welded on the backside.

Only 73-74 had the license plate bracket

pic

That bracket is on all 71 - 74 valences

It won't seem to mount to my late build 71, were the RT and non-RT rear panels different to accommodate different valances?

No the panels are constructed the same way

Can you post some pics as to why it doesn't fit?

I have two late 71s

I was already thinking that, will post tonight. Thanks!

So that answers the year question but why? Was it to stop it from flexing or crash standards?

If I had to take a guess...

Probably a cost savings measure. The updated design looks like it would be easier/faster to install on the assembly line. Less "loose" brackets to deal with exc...

Why what?

Why did it change from the 70 design to 71/72 design? Cost savings! Get rid of all those extra brackets and extra hardware.

From 71/71 to 73/74? To get the plate to line up with the light because of the safety bumpers