I couldn't find any direct LED replacement units for the old Marathon units in our 78 Ambassador...so I started to nose around one of my local Trucker's supplier of Chrome and LED accessories.
I found that the LED units in the front fender type turn signals were real close in size. I was going to have the store owner order only the RED LED units, but had a pile of used/come backs that he let me rummage through to get four good RED LED units...all for $20...a real score!!!
I had to grind all four edges to make them 'square'...they had a slight curve. I also had to grind a 'notch' on the back so that they would recess into the AS's tail light casting where I removed the Marathon type lens and 'bucket' that held the old bulb.
I also had to slightly notch the mounting holes 'inward' toward the center, about 1/8 inch to match the screw holes...I used a small bit from my router to do the job neatly.
I can't believe how much BRIGHTER these LED units are compared to the old light bulbs! You couldn't see much light from the old units during the day...and now they stand out for all to see! At night they are 'blinding' and can't be missed...I hope!
Click on image for larger view:
Here's the entire rear view...there are two tail/stop LED units on each side; on both sides of the Back UP lens (unchanged). The side corner 'marker' type light have been upgraded to an LED unit also. Red/White reflective tape has been placed on the bumper. The three upper Marker lights are also being upgraded to LED units next week.
Here's a close up view of the LH assembly.
Here's the kind of Large Truck type forward/fender LED Turn signal units that I removed the RED LED units from: