Head bolts, does this make any sence???
GM changed the length of some of the head bolts in 2004. The '99-'03 engines had 16 long ones, (6.50? overall length) and four short ones, (4.40? overall length) along with 10 small 8.0 mm bolts. In '04, GM started using all short bolts (4.40?) to avoid the stripped threads that were caused when people put the short ones in the deep holes and tried to torque them down.
Sounds just the opposite?

