Tonight I fully finished removing the LPG kit that was in my car before. The only thing left was to connect the 2 PCV hoses. These photos show the result of this in a couple of pictures.
The little cap sitting on top of the air cleaner used to seal off the PCV port on my carb. I forgot to put it away before making the pictures ;-)
The valve cover I replaced and the 2 hoses I hooked up.
And then it was time to see if the engine would still run. It hadn't run for a few months so it didn't start right away but eventually... it did! :-)