I was curious why the valve covers for these cars were made with a third hole? Yes, two out of the three are used for the wire looms, but what is the the third one for torwards the back of the valve cover?

On late model 240Zs they are for the choke cables although 280Zs don't have chokes.

So what should you do with that third hole?

These engines were not only installed in the Zed remember - don't forget they were also used in the RHD, Skylines/240K/240C/260C/280C/Laurels/Patrols just to name a few. Not all of these would have rod operated accelerators so maybe the other hole was used for a cable operated accelerator on a RHD car - most all share the same rocker cover. Most of the what some consider rare big NISSAN valve/rocker covers were from these other models usually the 1980+ models. The latest model I have seen with a L6 installed was a Laurel C31 1984.

double post sorry about that.