Well really the 79 still uses the same turn signal as the previous models. The bezel was extended but you can swap the 79 bezel onto and 73-79 without anything else. Add the lower stainless extension on the area between the grill and bumper and the inner grill and a 73 would look like a 79.
80 was different. I think it still uses the same core suport and the 73-79 but the head light bucket is different to accomidate the square light if so equipped. Then the turnsignal was different to match the square headlight bezel. 81 up was a major front clip change. They went to a fixed cowel peice. to swap a 81 up front onto a 80 or older you will need to swap all sheet metal, winsheild wiper linkages to get the taller version that will stick through the cowel peice and modify the cowel box to acceped the newer style hood hinges.
Women dig dents and flat paint!
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75 Jimmy, Dollar
Grim-Reaper