First welcome to the site - hope you find the support and information provided here helpful in your concours related endeavors
You will find in most discussions and threads here on the site that the general option is to not copy other examples since there is no way of determining if your car originally had that mark or daub. We have found that over the years owners and builders have felt the pressure to add or place markings on their car because everyone else was doing it and they would apply marks from other cars, plants, years and so on, leading to a fair amount of less than reliable out there - and it got worst once the pictures started showing up on the internet.
Because of the "borrowing" and migrating these details have done in the past I tend to hold back and not share allot of paint mark details publically (have over 8000 picture examples currently labeled) and don't share them until I can get a number of them that agree with one another from the same plant and application. The others might have only been applied on a single part so this helps not create more.
Of course the first place to find this information would be the car in question - if it has been been redone some point in the past. Unfortunately for Shelbys - after 50 years or so that has become less and less likely
From this we get typical markings and placement so lets see if we can help with those for your application.
For the housing of a spring 66 GT350
- You have already seen the DSO handwriting on the rear of the center section. Depending on who applied the writing at the Sterling plant it could have been applied vertically from the drivers or passenger side and in white or yellow paint. Yellow so far seems to have been the more common of the two colors. One worker like to add a period after the "D" and "S" on those examples.
- Locator mark at the brake junction attachment hole on the top drivers side of the housing. Brush mark from about the hole down the back side of the housing for 3 or so inches, a drip or a longer past could produce a longer final look. A light blue or a green colored paint has been seen used for this marking
- Would not recommend an X. That IMHO is something you saw allot 20 years ago on restored cars but in my experience has not held up to research and documentation in years since from original unrestored examples and period pictures.
There are a couple of other markings that have shown up on some original examples but not enough information is identical so haven't included those this time
Related to the housing
- Rear end housing vent hose typically has a yellow daub on the hose where the clamp holds it to the under body of the car. Make sure you use a paint that will not react with the rubber hose as some does
- The U shaped axle housing to rear spring hardware is often found with a small (approx 3/8" dia) pink daub on each of them at or sort of near the top surface visible once mounted.
For others viewing this tread remember that these details apply ONLY to the car in question. Do not use or apply them please on other applications without first doing your homeworkHope this helps and again welcome
