Before I completely disassembled the Challenger for restoration, I had slight exhaust leaks at both manifold/head pipe joints. Since the car is apart, I took the exhaust manifolds (RH#2899879 / LH#2951865) to a well rated machine shop to clean up/true up the outlet flanges. (I know I have to "true up" the head pipe flange faces, too.) I was expecting the machinist to remove a couple hundredths or so. Instead the faces now have a "front to rear" taper. The front of each outlet flange is about 0.330" thinner than the rear of the flange at the bolt holes. I can only think of three options on my end: Have new head pipes custom made with the flange at the correct angle when I put the exhaust system back on. Have a machine shop taper two 1/2" exhaust flanges to match the manifold taper and install them between the manifolds and the existing head pipes to get close to square again. Buy replacement manifolds - a significant expense I hadn't planned for. What to do? Suggestions? Thanks.