I just bought a 2000 Chevrolet 3500HD with a VIN code F 6.5 TD, and California emissions. It has the stock exhaust system, which has had pieces added/repaired by the previous owner (an HVAC Company with a bunch of trucks).

In addition to the muffler, there is what I assume to be the Cat Converter upstream closer to the turbo.

I live in Utah, and there's no emissions required on this truck because it's GVWR exceeds 14,000 lbs.

I want to install a 4" exhaust, but I'm concerned that not having the Cat Converter might cause problems with the ECM?? or other engine-based computer.

Can anyone enlighten me on this?

Thanks,

SmittyIMG_20210329_175845718_HDR.jpg