In regards to the service manual intake torque spec, keep in mind a lot of service manuals incorrectly listed the rocker shaft bolt torque for the LA engines at 30 LB FT. Lots of people have broken those 5/16 bolts off, too. That's in there wrong. It should be 15-17 LB FT. So it's possible that 12 LB FT is incorrect. It certainly sounds like it's not tight enough to me. Just one man's opinion.
