Aproximately 4"wider and 2" taller. It was really pretty easy. Cut the hole. Roll a piece of sheet metal (I used 10" PVC pipe ). Push it up from the bottom. Tack weld, trim the excess, and finish weld. Mine was done for shield clearance and ease of trans removal. It comes out in 30 minutes.Thanks for the advice looks like I might get the car. I was planning on reshaping the tunnel for a future 5 speed conversion. DVW how much did you widen the tunnel?