According to the 1996 Ford Thunderbird Owner Guide :
( " regular " unleaded gasoline , 87 octane is used in your 4.6 )
There are number of different kinds of gas you should use. The gas you should use depends on the situation.
Regular gas should be fine
unleaded
You should use 93 Octane in your bike.
Premium
93
Regular
dot 3
rocket fuel
Lava briquettes
Most professionals recommend that you use high octane gas. Like 92-94 octane.
Regular 87 octane