Some came with confined production head P8R which experienced 33mm ingestion valves (normally found on VTEC B-series) vs 31mm ingestion (non VTEC B series), and the head had an 84mm shrouding vs 81mm for all other B series heads. The B16B is like a shorter stroke equal of the B18 https://honda-b16b46551.ssnblog.com/38536032/the-smart-trick-of-b16b-that-no-one-is-discussing