Can a transmission be mounted slightly twisted? Tremec and Chevrolet seem to say, “yes!” for an F-body Camaro.
Here’s the backstory: for our LS3-swapped BMW E36 we decided to use the Tremec T-56 Magnum F transmission, because the shifter location nearly matches up exactly with the stock E36 hole. Even though it had to be slightly elongated by an inch or so and we were able to avoid purchasing a shifter relocation kit, it turns out this exposed a slight downstream problem.
If you look at the pics below, the shifter isn’t straight when we bolted it all up with a standard LS bell housing. The shifter and the transmission mount are twisted what looks to be about 5 degrees, but the main case is straight. WTF!?

It took a ton of research to figure out what’s actually wrong and as usual, the fix turns out to be simple – buy a bell housing from an F-body Camaro. Take a look at the picture below to see the key difference between an F-body bell housing (left) and standard LS bell housing (right):
See it? Notice the difference? The ruler is there to show that the engine-side flanges are level with each other, but the transmission side is twisted 5 degrees to the left for the F-body T-56 bell housing. That means the transmission main case mounts 5 degrees left and consequently, to get an even shifter you need to twist the tail case 5 degrees the other way, clockwise.
Why it was done this way is something we can only speculate on, but perhaps it was a packaging issue. Either way, to get the shifter to be straight, you need to use an F-body bell housing with a Tremec T-56 Magnum F transmission.