Even if you do use the ECS breather required to meet the California regulations back in the day, I still would not use the third nipple for its intended use on our old cars. It was there to take any evaporative fuel vapors escaping from the fuel tank and send them ultimately to the crankcase, thereby diluting the oil and in some rare cases also causing the oil pan to blow off during startups. A cheap, dumb idea by Chrysler to avoid the expense of using a charcoal vapor cannister. I will probably leave the 3rd nipple looking like it is hooked up just because I tend to be a purist, but it would not be functional, having accomplished that where you can't tell when looking under the hood.
