Mangum Racing 235cc LS1 Cathedral Port Cylinder Heads

Mangum Racing 235cc LS cathedral-port cylinder heads deliver CNC-ported airflow with a 6-bolt casting, increased deck thickness, and the factory-style 15° valve angle and valve locations. Designed for naturally aspirated and boosted LS combinations with a 3.900" or larger engine bore, each set is CNC machined, hand blended, inspected, and fully assembled.

Fitment: Minimum engine bore is 3.900"; minimum head-gasket bore is 4.060". Suitable for compatible 5.7L, LS1, LS2, and 6.0L combinations meeting these requirements. Stock-bore 4.8L/5.3L engines require Mangum's 229cc design. Verify the complete engine, gasket, piston-to-valve clearance, and valvetrain combination before installation.

Key Features

• 6-bolt Mangum Racing casting with increased deck thickness
• 235cc CNC intake runners, 99cc exhaust ports, and 63.5cc CNC chambers
• 15° valve angle with OEM LS valve spacing
• 2.065" stainless intake valves and 1.600" stainless exhaust valves
• Bronze guides, titanium retainers, Viton seals, and 1.250" steel spring seats
• Choice of PAC .650" double springs, TSP/PAC .660" polished springs, or PAC 1207x .700" springs

Airflow Performance

Manufacturer SuperFlow bench data. Intake tested with a radius entry; exhaust tested without a pipe.

Build options: Chamber milling and softening are available by request; contact SMGspeed before ordering a custom configuration. Verify final pushrod length for the selected camshaft, gasket thickness, and milling.