There's also a wildcard here. REPLACEMENT small blocks (R3, 340 Resto Blocks, etc.) are considerably heavier castings than original 318/340/360 blocks were. Most original blocks weighed in at around 165lbs with caps, replacement blocks are up around 220 (that's right in there with a vintage 440 or Hemi block!). Modern wedge and Hemi castings also wiegh allot more than vintage blocks.


So, it depends on which engine block you start with, not just which bolt on parts you use.