1986 Mustang 3.8L cyl. head torque.

The aluminum heads on a cast iron block require some gentle torque procedures.... It may not be necessary - but I suggest that you start near the center of the head and work out with each tightening step. This will ensure that you don't put too much pressure on a single portion of the head. The standard proceedure for the 3.8 V6 up until 1994 is as follows:
You will have some long and some shorter head bolts. Place a small mark on the long bolts to identify them during the final torque proceedure.

Step 1: 15 (on all bolts)
Step 2: 29 (on all bolts)
Step 3: 37 (on all bolts)
Step 4: Now, starting near the center of the head, loosen a single head bolt about 2 turns. Now, torque it down to about 15 (+/- 3 lbs) IF A LONG BOLT.
OR 11 (+/- 3 lbs) IF A SHORT BOLT.
Step 5:
After all bolts are set as described above, ....go over them 1 more time, starting near the center of the head and pull each bolt down another 1/4 turn (90 degrees).
You are done!!