TILT! The A-bodies made in Windsor in '66 were not Darts, they were Valiants. All '66 Canadian Valiants were Dart-bodied, front to back, and the sedan, hardtop, and convertible models were on the 111" wheelbase. Effectively they were Dart-shaped Valiants. Your ID plate decodes as follows:
L: Valiant
P: Premium (Signet)
23: 2-door hardtop
B: 225 Slant-6 engine
6: 1966 model
9: Built at Windsor, Ontario, Canada
149119: Problematic serial number. Should start with 2; see attached. An LP23B65 (Los Angeles) or an LP23B67 (St. Louis) car could have a serial number starting with 1, but LP23B69 (Windsor) serial numbers started with a 2.
No, there weren't any stick-on badges or emblems in '66. This car doesn't have them because it's not a Dart GT, it's a Valiant Signet (at least the part of the car with the ID plate is), and those didn't have C-pillar badges. This also explains the 4-speed, which was available on the '66 Canadian Valiant with Slant-6 engine. It's got various Dart parts on it (horn button, trunk lid lettering, ghost of hood lettering), and it's missing all its Valiant badging.
Given the discrepancy with the ID plate/serial number, and the mix 'n' match parts, you ought to be extra careful, but if you know what you're getting and what you're not, it could be a fun car. The running/driveability problems won't be hard to fix.
