Totally Dissapointed!!!!!
What KB pistons are in your motor ? They have 2 listed for 318s The KB167 flat tops which is 9:1 with a 68cc head or 9.5:1 with a 64cc head and the KB399 domed that will give you your 11:1 compression with a 64cc chamber.
You'll need to mill the heads to get a 64cc chamber. I see nothing wrong with using the KB pistons aslong as the ring gap instructions are followed.