340 Wedge, the biggest and last factory engine call out on a hood since the 60's Nascar racers were out to impress with their engine sizes. A unique decal for any maker, and the only one Mopar did that I know of

 I think this is the most factory correct of the ones I photograpghed and are posted here.

 I think on the streets I've only ever seen one of these, and never at a car show before.