Hi all,I just bought a 06 GMC with the 5.3 vortec what is the size 305,350 or what,and what is the HP,thanks Bob

its about 327 cid give or take a couple inches

I've gopt the 5.3 in my 2000 I believe it actually breaks down to a 323 or basically a 327.

finally found my chart it is for sure 325 cubic inch

factory ratings are 295 horse and 335 ft\lbs of torque in all reality you lose about 10% in the drive line

On my window tag, 06 5.3 it advertised 310 hp.