I recently pulled a big block from a chevy box truck. The owner told me it was not the original engine. The casting number is 14015445. Is this a tall block? How can I tell? I pulled the oil pan and it has a 4 bolt main.

Without looking up any numbers, simply note the area right above the water pump mounting bolt holes - tall deck blocks still have block above the top bolt hole, standard blocks do not.

Thomas

It's a 4 bolt main, standard deck height 454 block.
Good find!