Comp cams xe268h for 318

late 318 pistons have a depression in the center, which is called a dish. at .022 deep that may be 3cc's
adding it all up; 13+3+8.6gasket+63heads=87.6cc and at stock 3.91 bore this maths out to 8.45SCr......... not too bad, in theory.
Even if the dish is 6cc, you are still at 8.2
Just don't put police heads on to get 7.2....or less