Exterior Components› Body Panels and Components
Mr. Gasket
Ultra-Seal Header Gaskets Fits 1965-1990 Chevrolet 396-454 Mark IV Big Block Round Ports, 2.15 Inch Mr Gasket
SKU: M00S 5912
Easy — 1–2 hours
Description
These gaskets are constructed with a steel core laminate and a graphite facing, providing excellent heat resistance and thermal conductivity. The high-recovery material ensures the flange stays sealed even if clamp-load is lost, while the expanded steel core offers stability and maximum torque retention.
Fitment
Fitment Guaranteed
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Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.
Available on iOS & Android
Specifications
| Brand | Mr. Gasket |
| Part Number | M00S 5912 |
Buy with Confidence
Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.
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