You asked in a previous post if the engine is supposed to sit level in the car. I would say no. I would say that the carbs are supposed to sit level. If you look at a street hemi intake I think you will find it is taller in the back than in the front. I don't have a street hemi intake here to measure but a 65 race hemi intake is higher in the back. It is on a 2-1/2 degree incline. I presume this is to make the carbs level. So when you look at the valve covers they should be lower in the back by 2-1/2 degrees. Just my opinion.