Fits 1965-1990 Chevrolet 396-454 Mark IV Big Block. Square Ports, 1.85 Inch x 1.90 Inch
Designed for extreme cylinder pressures by high horsepower-high compression turbocharged, supercharged and nitrous oxide injected engines
Manufactured from three stainless steel layers, they resist corrosion, will not burn through or push out and maintain maximum fastener torque retention
Stress formed inner and outer layer embossments act like springs that rebound under flange clamp load, creating force to seal extreme pressures
Will not deteriorate from scrubbing action caused by different expansion rates in aluminum and steel materials
Total gasket thickness .075 inch