I am going to have to disagree about 3.8 blowing head gaskets due to low coolant levels. (I have a 91 T-bird., it blew under my brother's ownership around 96K. Still running at 158K, but the 3rd-4th band on the tranny is in sad shape.)
They actually had a sub-par gasket with a not so great cooling pattern which mixed together had a problem. The Supercharged T-birds had a different coolant pattern that didn't have this head gasket problem.
Either way, Ford solved the problem by using a better head gasket later in the 90s and made the improved cooling pattern standard. I seem to remember the better gasket being a metallic head gasket or something like that.
(I should also note that when my posts say 76vs8920, you have to take my comment with a grain of salt.)