Video of 348/409 heads being worked https://www.msn.com/en-us/autos/other/we-rebuilt-a-set-of-409-big-block-chevy-w-series-truck-heads/vi-BB1lSZ5b?ocid=U521DHP&pc=U521&cvid=f772db3688ed41df8afeb04fd83ed614&ei=42#details
