I posted this prior in my build thread but CPP is a true zero offset according to their tech REP. Now I have only mounted the kit on a drum hub during mockup. If it used the stock hub it would be pushed out by 1/8 each side due to the difference between drum and rotor thickness. I call and talked to the tech Rep to discuss this because I am very close on the inside with my setup. I ask him if this is the case. He verbally said no our hub is machined down to account for the difference between the drum and rotor and it is a true zero offset. There is a current post on other site the guy has a write up about his install using the Ebay version mentioned above installed on a 57. He claims it is zero offset. If it isn't it not going to push the wheels out anymore than 1/8 per side.
FYI willwood stock spindle brake kit pushes the wheels out .2 per side according to them.
Zero offset brakes kits fit stock spindles drop are not necessary to have zero offset kit.
Rocky