I have a Gen 1 and Gen 2. I raced him in in the Gen 1 that night. It is an ES with the 3.5 liter.
Interesting note though:
When we raced on an empty highway stretch with my Gen 2 with the 2.7 liter we matched. The thing is the 2.7 liter can rev high and hold it where the 3.5 liter is stronger but can rev up as high for long. Only problem with the 2.7 is acceleration off the line. The T Bird destroyed me.