Head bolts question + followup

[rkapteyn]

Check the length of the bolts.
The Champion engine had two bolts that were longer to bolt on the ignition wire bracket.
If you did not pay attention and replaced the shorter bolts with the longer ones ,the long ones will bottom out and not tighten.
Robert Kapteyn

[showbizkid]

Threads merged to keep the discussion together.

[Dan Timberlake]

1000 lbs of engine etc suspended by 2 bolts is about 500 lbs per bolt and at most 1000 lbs.

Tightening a 7/16" head bolt to just 45 ft-lbs exerts almost 7000 lbs of clamping force.
http://www.repairengineering.com/bolt-torque-chart.html

[Pentax645]

Most interesting data on clamping force. Wow.