I'm not sure how you are going to do that. you can lay both in the engine bay, tied up out of the way then when the motor is in and still up, you can install both. You should also install the plugs before you drop it, at least in the drivers side. The pass side isn't as much trouble. I've never heard of anybody installing either side header before engine install...maybe if you had the engine on the k-frame and were dropping the car down onto it.