Kelsey Hayes rotors
Well
@JDMopar seems to be right, this is an old SSBC kit. Hard to tell through all of the dirt and paint, but it is there on the calipers. Thankfully, they do still sell parts for it. Expensive, but parts exist. I guess I'm down to pricing out which is the least expensive: convert the car to big bolt pattern, having to buy axles for the rear, and use later brakes up front while also having to change the wheels, or buy replacement parts for what I have.