I just received my parts for my head gasket job and included were new Fel-Pro head bolts. Included with the bolts were directions to torgue the bolts to 47 ft/lbs.

The factory service manual instructions say to tighten bolts in several passes to 36 ft/lbs, then tighten an additional 90 degrees.

I am going to use the FSM procedure as stated above but was wondering if tightening to 47 ft/lbs would yield the same results. I am going to try a test when tightening to see if the additional 90 degrees and the 47 ft/lbs are the same.

Any input on this would be helpful.
Thanks

i agree i'd go by the factory manual but as you say may be the same out come

IMO, the difference between the two specifications is in the bolt stretch which results. The factory specifications stretch the bolt to a more precise degree. A 90 degree turn is a much more precise tightening to stretch than the pure torque specification of the bolt manufacturer, since the latter relies on clean or lubricated threads to a degree. Also, a torque spec can be fooling when you have a dirty hole in which to tighten the bolt. This type of hole prevents turning a bolt beyond a certain point because of an obstruction or defect in the threads.

I recommend using the FSM procedure and use the 90 degree final tightening.