New wheels/Tires before New engine installation?

Get your tires and wheels on the car to set the ride height. You will need the weight of the motor and transmission in the car,as well as the hood, another 50 lbs there, and all the fluids including full tank of gas. I dont understand what you mean by levelling the engine, are you doing a custom set of mounts to lower the motor into the car? You will adjust the torsion bars accordingly so the tire doesnt rub, and you get the look you want. I ended up adding 1.5" lowering blocks on the rear end, as my springs have a 6-5/8" arch.