I have Eddie marine thunder exhaust on my small blocks now. Wanting to go to CMI‘s. Will I have to have it retune or can I plug and play ?

I’d put in a wideband and let that tell you.

Very nice exhaust, but I doubt the CMI will show much if anything on the GPS.

If I get any gains I would be happy. I just really like the way the look under the hatch. I just don’t want to retune it. And I’m sure the sound will be better. The guy I had tune it said to put them on it will be fine. I have a lot of money in the motors thought it would be smart to bounce it around here. I appreciate all the replies .