I recently did the t5 swap in my 1990 740t. You will need to buy a 740/940 manual pedal box, it's up to you to source a cable clutch system or hydraulic pedal box. I don't believe there are any t56 to redblock adapter plates that anybody makes, I could be mistaken.
The biggest issue with the swap is the shifter relocation. With the mustang tail housing on the t5 (probably most common) the shifter is several inches too far forward. I had to modify my shifter with some quarter-inch steel to move it back. When the transmission is removed and there is room underneath the car you should hammer out the shifter opening as well. I believe if you find a t5 with a camaro tailhousing then the shifter position won't be an issue in a 740/940. Here is a photo of what I did
Lastly, the t5 really messes up your driveshaft angles, I had to raise my transmission 3/4inches upward from the max height using the Yoshifab 740 t5 transmission cross-member. So at maximum height using the adjustability within the cross-member, I had to shim it up an additional 3/4inch. You will need to buy adjustable torque rods or make your own to raise the pinion angles as well.