I had both a '94 and a '97 T-Bird with the 4.6. While they were nice cruiser cars (especially the '97) they are not really hot rod material with just a stock 4.6 V8. Now, if you were to find a late Mustang with a blower engine to install in that car along with some differential ratio that's a lot better........

They are heavy, have an IRS that has some weaknesses, the original transmission has a torque converter that's junk, the brakes, unless you are lucky enough to have one with the4 wheel discs/ABS option are crappy.

But with that said, the V8's are a nice long haul cruiser, will get up to 27 mpg open road. 18-19 local driving and go faster then you can ever drive it. It does NOT make sense to make one out of a 3.8 when a 4.6 car can be had ready to go. I have seen my '97 within the past few weeks - and it still looks great.