Dtomi SBC Copper Header Gaskets for Small Block Chevy 327/305/350/383 Oval Port — Pair, Heat‑Resistant Seal

Dtomi SBC oval port copper header gaskets create a durable, leak-resistant seal between the Small Block Chevy cylinder head and aftermarket or stock exhaust headers.

These precision-cut copper gaskets are designed specifically for SBC (Small Block Chevy) engines — including 327, 305, 350, and 383 displacements — and replace part number PH306. Built to resist heat fatigue and blowout, they offer a long-lasting seal that helps preserve exhaust flow and reduce unwanted noise from header-to-head interfaces. Each package contains two gaskets, and Dtomi backs the part with one year of quality support.

How do these copper header gaskets improve my engine's exhaust connection?

Proper sealing at the header-to-head joint prevents exhaust leaks that can lower performance and create irritating noise. Copper's thermal properties allow the gasket to conform under heat cycles while resisting degradation better than softer materials, maintaining back pressure and helping exhaust scavenging work as intended.

• Precision-cut to fit SBC oval-port headers without trimming.
• Copper material conforms to mating surfaces for a tight seal.
• Reinforced construction reduces blowout and shrinkage over time.

Will these gaskets fit my Small Block Chevy (327, 305, 350, 383)?

Yes — these Dtomi gaskets are manufactured for Small Block Chevy engines that use oval-port header flanges and are listed compatible with 327, 305, 350, and 383 displacements. Confirm the flange shape and bolt pattern on your head and header before ordering if you have an uncommon aftermarket component.

• Replaces OEM/reference part number PH306.
• Specifically cut for oval port SBC header flanges.
• Sold as a pair so both sides can be serviced at once.

How easy is installation and what do I need to know before replacing them?

Installation is straightforward for anyone familiar with removing and reinstalling exhaust headers. The gaskets are made to fit without trimming; ensure mating surfaces are clean and flat and use the correct torque sequence for your bolts to avoid warping the header flange.

• No trimming required — drops into standard oval-port flange openings.
• Clean mating surfaces and inspect bolts/studs before assembly.
• Follow proper torque specs and a progressive tightening pattern.

How durable are Dtomi copper header gaskets under repeated heat cycles?

Copper withstands high temperatures and repeated cycling better than many soft composite gaskets. Dtomi’s construction resists common failure modes such as shrinkage and blowout, giving longer service life and reducing the need for frequent replacement in daily drivers and performance builds alike.

• Resistant to heat fatigue and thermal cycling.
• Reinforced to minimize blowout risk at high exhaust pressures.
• Supports consistent exhaust flow and performance retention over time.

Who is this for: These Dtomi copper oval-port SBC header gaskets are meant for mechanics, home DIYers, and performance enthusiasts working on Small Block Chevy engines (327, 305, 350, 383) who need a reliable, precision-fit exhaust seal. Choose them if you want a tested, drop-in replacement for PH306 that balances conformability and durability for street or mild performance use.