Firk its just running a std stroke 440 Wedge with factory cast-iron heads.
Say, instead of a Tremec, why don't you try a stall-converter in front of the T400? With the massive torque that puppy puts out, it would just be the best combination: outrageous acceleration when you plant your foot hard, yet still retain the smoothness and elegance when dawdling around the suburbs. Mmm, high-stall (say 2800rpm) would only be around $1K - $1200 for that. Much cheaper than a Tremec! I have driven a Jag with a manual, it was very truck-like, ruined the driving dynamics of the car................................................................