The only useful digit of that stamped code is the "D" which might be translated to a specific year and size engine with the right ID number list. The casting number on the driver's side of the back of the block near the bellhousing bolt circle might be more useful.

http://www.yearone.com/updatedsinglepages/Id_info/gm_engine_id/gmidimages/impala63.jpg

Edit: If, indeed, the engine is a 1963 model, the suffix letter indicates it was a 283 2-barrel engine.
Jerry



Last edited by Hotrod Lincoln; 05/13/2011 7:07 PM.
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!