Did you know that the lighting build specs for the 11 footer (when it was modified, post Pilot configuration) called for blue light to come from behind the grills on the nacelles (the grills that run the length of the inside of the Nacelles where the Intercoolers are)? They nixed it because of time, money, and the fact that the Nacelle steel and wood construction wasn't conducive to quick modification. So, as designed, the TOS Enterprise would have had blue light coming from the Nacelles, just like the rest of Trek-dom.
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