Some arrived with minimal creation head P8R which had 33mm intake valves (normally uncovered 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. Making use of the basic principles on the REV procedure, VTEC https://jdm-honda-replacement-eng71357.blogocial.com/the-smart-trick-of-b16-crate-engine-that-nobody-is-discussing-75669739