Dart 19574030M Pro 1 BBC Head

Pro 1 BBC Marine 355 Cylinder Head
Bare Casting

Every intake port, every exhaust port, every valve bowl and every combustion chamber is 100% CNC machined on special, dedicated Pro 1 castings. Our 5-axis computer controlled machining centers produce compound curves and complex shapes that no human could duplicate with a hand grinder.

Features:

• Premium alloy: Dart aluminum heads are cast from virgin 355-T61 aerospace alloy for superior strength and integrity.
• Bolt on compatibility: 2 degree rolled valve angle and standard spacing accommodates all stock accessories.
• Heart shaped 121cc chambers improve combustion efficiency.
• CNC machining ensures that every chamber has the same volume so that every cylinder maintains equal compression.
• Raised spark plug location improves flame travel for a quicker, more complete burn, producing more power.
• Multi-angle intake seats and radiused exhaust seats greatly improve air flow.
• Hardened exhaust seats are compatible with unleaded gasoline.
• Exhaust ports raised .300 to improve flow (requires 1 longer head bolts next to exhaust ports).
• Spark plug holes are machined for gasketed 3/4 reach plugs.
• Manganese bronze valve guides ensure long term reliability.
• All cylinder heads sold individually.