From my 2000 FSM (which should apply for a 1991)
(5) Tighten the engine cylinder head bolts in
sequence according to the following procedure (Fig.
56).
CAUTION: During the final tightening sequence,
bolt No.11 will be tightened to a lower torque than
the rest of the bolts. DO NOT overtighten bolt
No.11.
(a) Tighten all bolts in sequence (1 through 14)
to 30 N•m (22 ft. lbs.) torque.
(b) Tighten all bolts in sequence (1 through 14)
to 61 N•m (45 ft. lbs.) torque.
(c) Check all bolts to verify they are set to 61
N•m (45 ft. lbs.) torque.
(d) Tighten bolts in sequence:
² Bolts 1 through 10 to 149 N•m (110 ft. lbs.)
torque.
² Bolt 11 to 135 N•m (100 ft. lbs.) torque.
² Bolts 12 through 14 to 149 N•m (110 ft. lbs.)
torque.