I should have remembered this because I have been in the engine bay a couple of times but there is still a lot of memories lost from my brain since I was ill.
This is Tim's thread about your car when he had it.
http://challenger.mpoli.fi/forum/viewto ... ims+70+440
Your next step is to check that the number on the dash pad matches the one on your inner fender plate. Your dash pad should read JH23008173291 and the "8" might look a little odd (more key hole shaped) so tell us if it is like that.
Then check the other numbers under the hood. Look at this photo to see where they are. Your plate is on the wrong side of the engine bay by the way.