Hi guys looking at purchasing this engine with these casting codes , just need to confirm if it’s a 1957 371 engine ... thanks

 

Hi guys looking at purchasing this engine with these casting codes , just need to confirm if it’s a 1957 371 engine ... thanks

 

No, that's not a 371 block casting .
That number checks out to be a 52 or 53 303 .
There should be a number stamped in the deck surface between #1 and #3 exhaust ports.
Should be visible by looking straight down between exh. manifold and head .
Post that number and I can be more exact .