Got this off BigBlockDart.com
OEM Mopar Engine Weights
Here's a small list of [approximate] weights for stock engines.
Note most of these are fully dressed engines with stock parts.
We all know the savings to be had with aluminum intakes, ect...
331/354 Hemi with alum. intake and water pump - 504 lbs
392 Hemi with alum. intake and water pump ------564 lbs
Slant 6 -----------------------------------------525 lbs
273-340 ----------------------------------------525 lbs
360---------------------------------------------550 lbs
361-400 ----------------------------------------620 lbs
413-440 ----------------------------------------670 lbs
426 Street Hemi ---------------------------------765 lbs