This is all second hand info so it might not be 100 % accurate:
Spirkoff - 2 torque converters, then had a small fire
Collins - cam / timing issues
Ickler - never started
Vessels - cooked his motor
Vildolsola - ventilated his block
TSCO ( Weyhrich ) they did finish
Meyers class 10 won / class 1 car lost a motor
Ragland - some type of electrical issue ( ignition related )