My manual says, 225 in-lbs no more no less. And I understand there is slight difference between different torque wrenches, but I believe 225 in-lbs is tight enough considering the standard torque value for a 5/16-18 bolt is 160 in-lbs or if you have the 3/8-16 bolt is 270 in-lbs. I'm not really sure how much torque you expect from a 5/16-18 bolt on a aluminum block. I hope it's not 225 FT-LBS!