From the front edge of the COWL to the back edge of the scoop is 3.5 inches (so you can have room to adjust the hood). Remember that your "hole" needs to be and inch or two inside of that for the scoop to be bolted down and more then that in the front so you can run your spars down. I am running a AAR fiberglass hood and you may be cutting into the frame a bit and that needs to be finnished off as well. I had the motor in and then cut as to fit the cross ram.