My wipers were already installed at B & B. The motor mounts we put in. I don't know if it is the best way but here is what we did. Basically we fit the mounts to accomidate the motor. We put the motor in the car (still on engine hoist) had the mounts on the frame and adjusted accordingly to make sure headers were in the correct postion and to accomidate spacing in the front for the timing pully. Really there is only and area of about 2-3 inches that the mounts are going to go in. After everything was in place we tack welded the mounts into olace to keep there for the moment. Pulled the motor and finished welding. Also, we had the tranny on the motor to make sure everything was going to fit properly. Make sure that you have adequate room for your shifter so you are not to close to dash. Don't want to install something twice
Good luck.
J.A.