Yes, PULLEYS is a Scrabble word!

Letter values in Scrabble US: P 3, U 1, L 1, L 1, E 1, Y 4, S 1.

Is it a valid word?

PULLEYS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a simple machine consisting of a wheel with a groove in which a rope can run to change the direction or point of application of a force applied to the rope

Also: pulley-block, pulley block.