https://news.classicindustries.com/restoration-tips/mopar-lighting-guide-bulb-charts/

This says either #89 or 90. You don't have much room since the bulb has to fit inside the glass globe.

I searched and searched for an LED replacement but all of them were too tall. I ended up finding a conversion socket on E-bay that allowed me to install a 194 style LED in that location.