Head chamber size..??

[WILMASBOYL78]

I have a pair of chevy BB oval port open chamber heads. Casting # 6272292 dated A1872. According to Mortec charts these are for 71-72 402 and 454 motors. They list heads CC's for most of the heads in their file but not this one. Colvins book shows a similar head with a 113cc chamber. Thinking about using them for one of my projects with the obvious upgrades. The engine they came off was a CTB code 1972 402. Just wanted to know the chamber size for these heads before I start. Any help would be appreciated. Tom