That doesn't make any sense, and you repeat it in your last post. If you really mean leave the tranny bolted to the chassis it will not be easy to line up the engine with the tranny input shaft because it will be difficult to wiggle the engine and and rotate the crank to line up with the tranny shaft. If the rear wheels are off the floor you could have someone rotate the tires a bit to help the line up. Otherwise disconnect the drive shaft so you have access to the tranny rear to rotate the input shaft for line up.
If you get it done your way let us know the details.
