I have a dim memory of my Dad's '66 Sport Fury owner's manual having a couple leaflets for Airtemp & such.
Could be that the auto-lit sellers like Irv Bishko (try Ebay) might have complete ones.
I looked forever for the Hemi OM for my '68 RR, found one or two in 30 years, but they were very expensive.
'66s might not be so spendy as that's the highest-production year, but I'd bet they're pretty valuable.

Nice Dart project ! If it's getting enough muffler, that's gonna surprise people...