Ok. Here's what I've found out spec for spec with the differences of the two brakes in question. There's not much of a difference in thickness but the SS brakes are larger in diameter
Camaro SS
77 C20
I understand that I'll be using a lighter duty wheel but my entire trailer loaded with the goods is about 5000lbs. As far as the rear goes I actually have a Dana 44 out of a 2008 srt8 jeep Cherokee that I can use. It has the big brembro 14" brakes on it from the factory. I'm thinking that is more heavy duty than a 12 bolt and maybe even pretty close in strength as the stock 14 bolt.....