Bottom-stop failure on these engines is nearly unheard of because of the significant bolts and generous caps hooked up to the forged large alloy steel rods. Some arrived with limited manufacturing head P8R which had 33mm intake valves (Typically located on VTEC B-sequence) vs 31mm consumption (non VTEC B sequence), https://arthurqahji.blogdal.com/29365820/5-simple-statements-about-b16-engine-for-sale-explained