This is a quick guide to help when replacing head gaskets on a Subaru. The torque specifications for the heads along with the sequence is a bit involved.
1) Tighten all bolts to 29 N-m (3.0 kgf-m, 22 ft-lbs) in alphabetical sequence.
2) Then tighten all bolts to 69 N.m (7.0 kgf-m, 51 ft-lbs) in alphabetical sequence.
3) Back off all bolts by 180″ first; back them off by 180″ again.
4) Tighten the bolts (a) and (b) to 34 N-m (3.5kgf-m, 25 ft-lb).
5) Tighten the bolts (c), (d), (e) and (f) to 15 N.m (1.5 kgf-m, 11 ft-lb).
6) Tighten all bolts by 80 to 90″ in alphabetical sequence.
CAUTION: Do not tighten the bolts more than 90″.
7) Further tighten all bolts by 80 to 90″ in alphabetical sequence.
CAUTION: Ensure the total “re-tightening angle” [in the former two steps], do not exceed 180″.