I am wanting to get a hooker cat back for my 89 formula: 350 TPI 5.7L, but I have the dual cat setup of that year. Hooker is said to not work with dual cat, but single. But my 8th digit in my vin is 8, which hooker said would work with the cat. So would the hooker cat back work? Is there anything a muffler shop could do to custom fit it on? Thanks a lot!

Yeah, any decent exhaust shop should be able to handle the custom fit. You can just cut the i-pipe back a bit from the flange to make sure that the exhaust has the straightest flow possible. I just replaced the entire exhaust, and the shop fabbed up a small section of pipe where a certain piece of emissions equipment is supposed to go. Took 10 mins and cost me $20, including all the extra welding he did.