Two cars may look identical on the outside, but you don’t really know what you’re driving until you kick the tires, pop the hood, then fire up the engine. Institutional reforms aimed at eroding patronage and democratizing party politics in South Korea have led to counterintuitive and unexpected outcomes, I argue, because political scientists and political reformers alike have failed to “pop the hood” to truly understand the mechanics of informal patronage and intra-party management in South Korean political parties. This study “pops the hood” so to speak, by theorizing the effects of informal patronage on formal party management, and then linking these intra-party processes to the stability of party organization. Using this model of the “engine driving party organization”, we can better understand the effects that institutional reforms have had on patronage and party stability. While the focus of this study is on South Korean party politics, the comparison with Taiwanese party politics provides a useful counterpoint or control.