Exhaust Rules Update
#39669 from B-Spec/C-Spec Committee · Rule change · TB 26-03 (2026-03 Fastrack)
In GCR, Section 9.1.10.E, change as follows:
"25. OEM or approved primary/upstream catalysts are required unless a vehicle’s spec line has lists an approved
header listed or is specifically permitted s to remove ing the catalyst. The primary/upstream oxygen sensor must be installed and
functional. Secondary oxygen sensors and catalysts may be removed. The exhaust system downstream of the primary
catalyst/approved header may be replaced is free provided the system retains the original routing and exits the body in the
approximate location(s) as the OEM system. Single exhaust systems that are cosmetically split into dual outlets may use a single
outlet. OEM heat shields and/or exhaust heat wrap may be used."