Re: more numbers help please
 

Look here.
http://www.nastyz28.com/chevy-engine-code-stampings.php

Re: more numbers help please
 

here is the casting number

3935439..........date 6 14 68

but i still cant find anything on the BY suffix....possibly a marine block because it did have a 2 gear geardrive in it which would make the cam spin backwards for more torque in a boat ?? make sense to anyone ???

Re: more numbers help please
 

The only 3-character suffixes I've seen that start with a number are marine or industrial engines; sounds like a reverse-rotation marine engine.

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