The stock track width on my Challenger is 59.8", Nearly 5 feet! 'Cuda my be a little narrower but not by much. A lot of drag cars are narrowed in the front. I don't know why you would want to replace the stock inner fenders and associated stuff that it just in the way when working on a hot rod. I would look into a 1 piece fiberglass front end from maybe Glasstek. Sounds like the car is already cut up and I would just go with it.