318 POLY

318 poly is the A block
273, later 318, 340, 360 are LA block.
oil pump, timing chain and gears interchange, oil pan(not 360), front cover & water pump are year specific.
crankshafts including strokers will work with the 273-340 Journal.
You can bore the block to 4in. or a little more as in 340 bore size.
Same bellhousing bolt pattern as the LA.