Motor plate thought?

You can install the assembly from the bottom without the water pump & then install the motor plate , along with the water pump. It isn't necessary to use the motor mounts unless you just really want to. A 1/4" motor plate shouldn't cause any interference problems, you may have to space the alternator out for the 1/4" plate. If your goal is more of a street car rather than a race car, I would use the factory motor mounts as all of the vibration will be transmitted through the unibody with a motor plate. My Demon is motor & mid plated, but it's a full time race car. Good luck with your build.