Got my Mach1 manifolds today. As shown in the pictures it is a far better piece. It can be ported out to 2.5" to match exhaust pipe. The ports that mate the heads are bigger also, if you see the Mark VIII ports are smaller. Instead of modifying my steering shaft I am going to get a j bend tubing and go around the steering shaft. This will be cheaper and easier for me. Cut the driver side cat off the Mark VIII manifold and placed it in the approximate position. I am using the egr tube to hold it. The openings in the cat is 2.25" as seen on my caliper. I will weld the new tubing to it over the outside. I can open it up to 2.35" That is the id. Of 2.5" tubing so everything will work well together.