Some came with constrained creation head P8R which had 33mm ingestion valves (Commonly found on VTEC B-series) vs 31mm intake (non VTEC B series), and the head experienced an 84mm shrouding vs 81mm for all other B series heads. The B16B is like a shorter stroke equal in the B18 https://b16engine12345.jiliblog.com/96155353/how-honda-b16b-can-save-you-time-stress-and-money