My super low mileage '66 Hemi Coronet also had black painted lower control arms. I always thought they were original.

Cass, the drivers side control arm on this car, the one that is black painted, I would also assume to be original to the car. The passenger side however is the side that has had the fender replaced and looks like a bump to the wheel. I am going to try to locate the dates on the control arms as I get it on apart.
Matt

Just to be clear, there have been some 66 cars documented to have black painted lower control arms from the factory, I have seen them both ways but the black is less common in my observation. That said, I have not seen any from later year cars that were black. Also, 66-67 LCA rivets don't have date codes like later years did, again, in my own observation. .02

Thanks Scott for your help. I can use all I can get.
Matt

Got the suspension apart tonight, the drivers side is original the passenger has been replaced like we suspected. It has the dated rivets, and surprising seems to have a lot of the gold coloring still on it. I will have to be on the look out for a nice passenger side 66/67 lower control arm with sway bar tabs.
Matt

The replacement passenger side. With the dated rivets. Also note the difference in the plate the lower control arm bump stop attaches to.
Matt

The original also shows that it was dipped in black paint (as opposed to sprayed) which is correct.

yes that is what I thought too Scott. That's one reason I wanted to show the runs and how it appears to go away from the end like it was dipped. By the way you don't have an extra passenger side lower control arm do you?
Matt

I don't have any 66 stuff at the moment but I'll see if I can hook you up

Got some more work done tonight. Also some other details I took pictures of like the dates and part number on the torsion bars, leaf spring part number, some of the under bottom paint, and the 66 only leaf spring clamps.
I’ll post some pictures.
Matt

Did a little K frame repair and got the old 383 mount locations off and cleaned up. Now to have the K frame cleaned up and powder coated.

The leaf springs and clamps.
Matt

Some undercarriage pictures, one under the gas tank and a couple of the passenger floor pan showing the original primer and green overspray.
Matt

A few more pictures the rear exhaust hangers and the original fuel line clamps.
Matt

The original fuel sending unit. Unsure if the numbers stamped into it are the date, if so maybe 07 week of 1966, not completely sure.
Wish the portion inside the tank wasn’t rough.
Matt

Got the leaf springs out of the car, not for sure but it looks like to me they may have been black originally too. They are dated 75 6, so I’m going to say 75th day of 1966. If anyone knows for sure on the spring color let me know.
Matt

The entire leaf spring assembly was dipped in black. They came in natural unpainted as well. You've got plenty of evidence there to show yours were black.

Thanks Scott. In your opinion what is the best way to clean them to get them ready to repaint?

Disassemble them, use paint stripper to get the remaining paint off. Get a piece of PVC tubing (4" dia or so) cap and glue one end, add spring leaves, soak completely submerged in Evaporust overnight. Remove, rinse with solvent (not water). Buy real zink interleaves and new clamps (Frank Badelson sells them). After assembly clean them well with solvent to remove any oil or grease then make a trough to dip coat them in the paint. A wood box lined with heavy plastic or sprayed in a heavy coat of Flexseal works well, use a gallon or so of cheap gloss enamel paint (tractor supply store) thin with recommended solvent to water like consistency, use wire to hold spring eyes, dip in paint, let them drip dry over a catch cloth or paper.

Great project, I'll definitely be watching this one. Evaporust can clean prusty parts and will not disturb the paint. It also leaves te metal appearing original and untouched Vs glass beading with leaves and etched look on stamped steel parts.