I'm doing the LS1 brake upgrade. The install directions I'm using say I need the following :
Floor Jack
Jack stands
12 mm wrench
15 mm wrench
16 mm wrench
18 mm wrench
C-Clamp
Flat Stock
Loctite Thread Locker
Brake Cleaner

Whats a "flat stock"
I have everthing else. Thaks.

 

Stock is term used for a pole of material (alum, stainless, steel, etc.) Basically it is telling you that you need a flat piece of metal that you can put between the c-clamp and the piston when compressing the piston back into the caliper to keep from damaging anything. Kinda of like putting a block of wood between the jack and the car to keep from damaging the car.

 

or you could use an old pad... or a real caliper piston tool. either way it will work ok