360 to a 408 how much quicker

Here's something to think about, we used to run an altered in a bracket class years ago. It had a 383,with a street dominator manifold a mild erson cam headers etc. It sucked up some air in the oil pickup and killed the crank, we did a quick rebuild on a 440 short got a RB version of the street dominator and ran it at the next meeting. I can't remember if it was ET or MPH it picked up but it gained either 1 tenth or 1 MPH but it wasn't both.