Where and What Size Hole?

My car (72 Duster) has been in body shop jail for over two years now (that's a story for another time). I'm putting a 383 with a Weiand Hi-Ram (dual quads) on top of it. Obviously, I have to put a hole in the hood. The hood is coming home for a fee other repairs I am performing and now would be the best time (before final prep and paint) to cut the hole. I know it would be better / more accurate to have the car with the engine in it, to measure and mark, but I am wondering if anyone has already gone through this or has a similar setup, that could share measurements, pictures, whatever. Thanks in advance