My block is stamped F030IYS just below the altinator and I haven't found any other stamps yet. Its on my 1966 K10 chevy truck. The truck was out of the Fremont California plant. I want to make sure it's a 327 and that it's original to the truck?
YS is the only suffix you need to look up. It is a 1966 327 with a manual transmission and has 220hp.
