I have worked in Automotive Production most of my life and still do. The way a line worker knows how to put a motor on the line would be to look at the build. This would be done in 1970 by looking at the broadcast sheet and seeing what number that is assigned to this S/O and VIN and go to the location that number is assigned and pick the motor up from that location and move it to the line and put it on the conveyor or other mech. 1971 Hemis are coded E74 but on the line they are coded diffently either 407 or 408 and this is on the Hamtramic Broadcast Sheets.

Back to the "N" code for a motor. N is to reference to a 383 4 barrel motor. The plant then decides if it gets what "N" motor via the difference already preset in the build.(AIR ETC) So getting back to the beginning of the post that Dan posted it all depends on what options were ordered on the car and then the Broadcast sheet would varify the motor with the code for the motor that would be put in the car.This number would corespond to the number on the broadcast sheet and then you either get a 5 extra horses or not.

As for Galen and his list,he can stuff it in the garbage.That is only one mans opinion of what RARE is and this has been stated before,sometimes rare does not mean desirable because only one person ordered a certain car does not mean anyone would want it. Forget that Galen list we all have are own lists of what rare is and with my Challenger it is still one of one with the options it has, big deal.Be happy you own one.