JBROPARTS Exhaust Manifold Gasket Set for Small-Block Chevrolet 283–400 CID — Steel-Core High-Temp Pair

JBROPARTS 1404 is a two-piece exhaust manifold gasket set engineered to seal square-port small-block Chevrolet engines from 283 to 400 CID with a steel-core, high-temperature construction.

When rebuilding or repairing a small-block Chevy exhaust manifold, the gasket is a small part that prevents noisy leaks, exhaust flow loss, and premature header or manifold damage. This JBROPARTS set matches the common square 1.50 x 1.50" port pattern used across many 4.3L–6.6L V8 applications, and it ships as a pair so both heads are covered during an installation. The gaskets use a heat-resistant facing over a steel core to withstand exhaust temperatures and help maintain a long-lasting seal.

Which engines and vehicles will this gasket fit?

This gasket set suits classic small-block Chevrolet engines and several compatible models of late-1990s GM and related vehicles. It covers multiple displacements and model years where the square port pattern is used.

• Compatible engine displacements: 262, 265, 267, 283, 302, 305, 307, 327, 350, 400 CID.
• Fits vehicles including 1996–2000 Isuzu NPR, select Chevrolet C1500/C2500 trucks and Suburbans (1996–1999/2000), 1999–2000 Cadillac Escalade, and 1996 AM General Hummer models.
• Replaces factory part number 1404 for like-for-like swaps.
• Sold as a set of two manifold gaskets for both cylinder heads.

What are the gasket's dimensions and construction details?

The gaskets are designed to match square exhaust ports and to resist the thermal and mechanical stresses of exhaust service. Their measured port size and a reinforced core help deliver consistent sealing.

• Port shape: square; individual port dimensions 1.50 x 1.50 inches.
• Core: steel-reinforced center for structural stability under bolt load.
• Facing: high-temperature resistant sealing material on both faces for improved leak control.
• Thickness and crush characteristics tuned for common small-block manifold flange clearances.

How should I install and maintain these gaskets?

Proper installation improves longevity and prevents leaks. Follow basic exhaust manifold procedures and inspect mating surfaces before putting the gasket in place.

• Clean both manifold and head flanges, removing carbon, gasket residue and corrosion.
• Check for warpage; replace or machine warped flanges to ensure flat contact.
• Use correct torque sequence and values for manifold bolts to avoid over-compression.
• Re-torque if recommended by vehicle service manual after initial heat cycles.

What comes in the package and what support is available?

The set ships complete and includes manufacturer support in case of fitment or defect issues. JBROPARTS provides options for returns or exchanges if the product does not meet expectations.

• Package contents: two JBROPARTS 1404 exhaust manifold gaskets.
• Replacement reference: part number 1404 for cross-referencing.
• Customer care: return or exchange available if you encounter product problems.
• Suitable for routine engine rebuilds, repairs, or performance header swaps that require square-port gaskets.

Who is this for: This gasket set is aimed at DIY mechanics, professional technicians, and classic truck or SUV owners working on small-block Chevrolet engines from the 4.3L through 6.6L family who need a durable, square-port exhaust manifold gasket. It’s appropriate for restoration projects, routine maintenance, and exhaust upgrades on compatible 1990s-era GM and related vehicles where correct port size and reliable sealing are required.