1989 328 Paint code Rossa Corsa 300/9?

Mine is also 300/9 (in the UK). Its definitely a lighter shade than the 300/6 used on 308s that I've seen.

Its been recognised by paint suppliers here OK so not sure why they can't find it for you.

 

You can get a perfect match from Color Doctor it works well on rock chips

 

Where did you look? - O'Reilly? / Autozone? / Nappa?

FER 300/9 is a Ferrari specific paint code that isn't used by other manufacturers, so it's not in enough mass demand for the big auto-parts shop to stock it - It would just take up space on a shelf, collecting dust for years on end.

(I would be surprised if they couldn't get it made up on special order though)

You're going to need to find a paint specialist who can mix up the correct formula and supply it in the form you require (touch up pen / spray can), and there are several on-line suppliers who can do it.

Something else to bear in mind:

Red is the weakest of all the colour pigments, and highly prone to fading from age/exposure to sunlight/exposure to other environmental conditions, so a paint company could mix up a batch of FER 300/9 and make perfect to factory specifications, but when it is applied to the car, the shade/hue doesn't match (at which point most people claim the colour hasn't been formulated correctly, not thinking for one minute that the issue could actually be with their car, and not the paint mix)

High end paint shops take multiple scans of cars they need to colour match, and run them through a computer program that can adjust the paint formula to create a perfect match to the paint on the car.

So if you do find a supplier, and then find it doesn't match your car perfectly, don't automatically assume they didn't mix the paint formula correctly.