I Love this kit and have quite a few of them. This is looking good. I would also lower the front. If I am not mistaken, you just flip the spindles over to lower the front.
To me, that Revell parts pack engine always looked a bit under-scale.
Unlike the Revell kit, the body on this is pretty darn good. For a bit more accuracy, you could sand the front of the rear quarter to taper it down as shown in the pic.