A plug valve assembly includes a valve carried in a valve body and including a spindle coupled to a plug. The spindle may have an appendage coupled to a sidewall of the plug, and circumferentially extending about a rotational axis less than 180 angular degrees, such that the spindle appendage is registrable with a valve body outlet to selectively reinforce the plug sidewall and thereby resist blowout of the plug sidewall into or through the valve body outlet. The spindle may be composed of nylon and the plug may be composed of liquid silicone rubber.