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:
- Special hard chromate surface treatment for corrosion and erosion resistance. This treatment is also available on aluminum Dart blocks!

- 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.