What? Putting in the transmission? Anything is possible with enough patience, but I would pull the motor. It would be faster and easier. The adapter plate fitting would be the hardest thing, though if you buy the Wilcap adapter it is supposed to be cut to shape already. If you are running headers they would surely get in the way. I would pull the motor and tranny and test fit everything while it is out of the car. My headers hit a raised bump on the side on the motor, the adapters bolt near the starter got in between the plate and tranny and needed trimming, and the mini starter hit the headers as well. All easily fixed with the assembly on the ground, but damn near impossible if it was in the car.