OK, so after ordering some new $110 "LED tail lights" from a vendor that used a flat panel with plug in wires, and NO 1157 sockets I thought I would be set, but what I got in the mail instead was two LED 1157 bulbs, bulbs use 1157 sockets and I dont trust em.
I find that 1157 sockets are either 45 years old or a cheap re-pop that tend to give me trouble, YMMV.
Not to mention these same bulbs are around $9 on Ebay.
So, I returned them in disgust and was ready to pony up the big bux for a new set from a popular vendor when It hit me....wait, all of my equipment trailers have LED tail lights and they have stop/turn function and are really bright!
So I run out and take one apart to see what was inside, I purchased them from Harbor freight and installed them but never bothered to look inside, now I must know.
It turns out that they are just a disk with a circuit board of LED lights, the one side had a license plate light but both had side marker lights scred onto the side of the disk, and they measured out to be just a tick bigger than my 65 mustang's tail light housings, so off to HFT I go to give them my $40 (no coupon this time
I get them home and strip them down to the bare bits and this is what I end up with. In this pic I had already unscrewed the side marker array of LED's and spun them around and super glued them back onto the post they were on, only this time instead of facing out the side they face front for more light.
Spun around. I did cut off the LED's used for the license plate light since it would make one side brighter than the other.
After trimming the ends that my fingers are grasping they just fit into the housings.
Now you can just use an adhesive of your choice or just shoot a screw through a corner to hold them in place so it doesn't bounce around.
In this video I learned that I did not like the panel close up against the tail light lens, sure it looks cool to see the LED's but the performance was much better when I recessed the lens just a little bit. It seems that those diamond cut patterns in these tail light lenses really "pop" when you put LED's behind them, they get a glitter effect.
And here is the end result, not bad for $40 and a few hours.