Milltek's HJS Hi-Flow Sports Cat for the Chevrolet Corvette C8 Z06 is a high-flow catalyst upgrade that swaps the restrictive factory cats for HJS high-flow units in T304L stainless, freeing up the flat-plane 5.5 V8 for sharper response and a harder note. It is built for Z06 owners chasing flow and sound gains at the source, and fits directly in place of the OEM catalysts.
What is the HJS Hi-Flow Sports Cat for the C8 Z06?
It is a high-flow catalyst section that replaces the OEM cats with HJS-branded high-flow cores, built in hand-finished T304L stainless. This heat-wrapped version (SSXCH111) adds a thermal wrap to help manage under-body heat; the standard version (SSXCH110) is the unwrapped option. HJS cores are chosen for a balance of flow and emissions-focused catalyst quality.
Who is it for?
It suits the C8 Z06 owner who wants to reduce exhaust restriction at the catalyst and sharpen the flat-plane V8 sound, rather than only changing the rear tips. Pair it with a cat-back for the fullest effect.
What does it include and what are the specs?
The system ships as a direct-fit high-flow catalyst section with HJS cores, thermal heat wrap and OEM-compatible connections.
| Material |
T304Lstainless, hand-finished |
| Pipe diameter |
3" (76.2mm) |
| Catalyst |
HJS high-flow sports cats |
| Options |
With heat wrap (SSXCH111) or without (SSXCH110) |
| Fitment |
Chevrolet Corvette C8 Z06, 2023 and later |
| Install |
Direct fit in place of OEM catalysts |
What are the limitations, and who is it NOT for?
This is a high-flow sports-cat section, not a decat, and it works best combined with a matching cat-back. Check emissions rules for your state before fitting high-flow cats. It changes flow and tone at the catalyst; it is not a full power-package on its own.
Every system is built in hand-finished T304L stainless. (Source: Milltek Sport, About Us.)
Last updated: 2026-07-01.
Designed in Tennessee and manufactured in the UK with 40+ years of performance exhaust heritage. Tested on the Tail of the Dragon.
Vehicle fitment
- 2020-2026 Chevrolet Corvette E-Ray
- 2020-2026 Chevrolet Corvette Stingray
- 2023-2026 Chevrolet Corvette Z06
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