Thanks to Mike for sharing.
There are already a few Tbirds running around with T-56's, but I don't think the owners post on here.
At most you just need to pound a bit on the trans tunnel to make some room for the T-56, from what I've heard you have to do the same for some of the Tremec 5-speeds.
but not every car or it's motor/cradle mounting is going to be exactly the same.
also ddperformance.com has some dimensions for the various transmissions.
The T56 shifter will require a different offset than the T-45, if I remember right it's a bit closer to the right spot, but I may be wrong.
Definately requires a different length shaft, I would hope a shorter one, but I don't know.
Of course if you have a 4.6 you have to make sure to get one with the correct bellhousing pattern, and to use a typical mustang clutch, you may have to get one with the right input splines.
There is a big benefit if you can run a .50 top gear with 4.56 or 4.30 gears, you get tons of torque multiplication down low, without sacrificing streetability and RRR's at high speeds.
It is however a heavier trans, and to get one that's rated at the 650 ft lbs you have to have the viper gear set with the 2.66 first gear.
Here is the Ford 4.6 T-56 with viper gearset
It has the following ratios:
The wide ratio version is also available:
Although I think some guys have mixed and matched gearsets to get a bit taller 6th gear on the wide ratio gearset,(yet retaining the lower first gear, etc)
Sounds like a fun project!!