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Choose H.O. GREEN cats for your Stingray build
Upgrade the front catalytic connections on your supported C8 Stingray with Kooks H.O. GREEN pipework. The flanged stainless set joins the OEM manifolds or matching Kooks headers and the OEM cat-back, with gaskets and a bolt kit included. Tuning is required for this installation.
SKU: 21803400
A defined high-output catalyst specification
The 3" connections use H.O. GREEN catalysts with 304 stainless steel outer bodies and a 4-1/2-inch-diameter, 300-cell metallic substrate. That gives you the exact H.O. GREEN specification when comparing it with the separate Ultra-GREEN connection sets.
Keep the factory front and rear interfaces
The flanged inlet and outlet use the stock bolt pattern. You can retain the factory manifolds and a rear system using the OEM connection, or pair the cats with matching Kooks headers. Plan the required tuning alongside installation.
Arrange the required tuning
Tuning is required for these H.O. GREEN connections. Our C8 Stingray ECU tuning service offers custom dyno or remote calibration for the listed Stingray. Contact us to discuss the complete setup.
Matching products
The Stingray Super Street headers give the listed Stingray an additional header upgrade using the OEM-cat interface. Tuning is required for the H.O. GREEN cats on this page.
Vehicle fitment
| Years | Vehicle / trim | Engine | Applicable SKU | Fitting conditions |
|---|---|---|---|---|
| 2020-2026 | Chevrolet Corvette Stingray | 6.2L V8 | 21803400 |
Ordering and delivery
Estimated lead time is 4-6 weeks. Delivery may be faster depending on stock levels. Shipping is charged separately.
Technical specifications
| Specification | Details |
|---|---|
| SKU | 21803400 |
| Applications | Supported C8 Stingray 6.2L LT2 years below |
| Pipework | 3" stainless steel |
| Catalysts | H.O. GREEN; 304 stainless outer bodies |
| Substrate | 300-cell metallic substrate; 4-1/2-inch diameter |
| Front interface | OEM manifolds or matching Kooks headers |
| Rear interface | OEM cat-back |
| Flanges | Stock bolt pattern |
| Included | Gaskets and bolt kit |
| Tuning | Required |
Frequently asked questions
Can I retain the factory manifolds?
Yes. The inlet connects directly to them or to matching Kooks headers.
Is tuning required?
Yes, for these H.O. GREEN connections.
Are these the same as Ultra-GREEN cats?
This set uses H.O. GREEN catalysts with a 300-cell, 4-1/2-inch-diameter substrate. Ultra-GREEN sets are separate products.
