C5 caliper pressure cast AL, late 4G F body cast AL, early 4G F body cast steel as you probably know. Can't beat c5/6 parts for price, effectiveness, options and off the self replacements
Sean, rereading the thread can't help but wonder why you didn't build a full frame. You are a beast! Keep up the good work of making us all jealous.
I was always worried about those holding position properly.