By the time I did my 3X setup I already had done the T5 so I had moved it to the floor but I can see how you'd have interference problems. Not sure on the duel exhaust although my Kansas Customs splits I was running are layed out similarly.
Do you plan on keeping the 3 speed or is their a trans swap in the future, and what Carbs are you going to run? The 3X is tight in a truck with standard carbs in my case with the two barrels I had to clearance the firewall.
Here's pics of my setup when it was going together the first time.
Steve
