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Dave Mackie Harley-Davidson Hi-Flow Heads
Complete Head Porting and Contouring Services
It's difficult to photograph our special shapes and contours. We have tried to show you samples of the finished product and let you judge for yourself. What we strive for
Before

After
is maximum air flow and highest possible velocity. Velocity is the key to efficient fuel atomization and "ram" effect which leads to maximum power and economy. This is especially important in Twin-Cam and Evolution heads. When modifying Twin-Cam or Evolution heads we retain the integrity of the original design while increasing both flow capacity and velocity, and improving atomization and ram effect. Great care is taken in the fitting of guides into all types of heads. Each guide is Sunnen-honed to assure that the bore is true from end to end and precisely fitted for valve stem clearance. The finest valve and seat grinding and cutting equipment is used to assure a truly concentric valve job with as many as six radiused and blended angles. Each step is critical and we feel we perform each with as much care and professionalism as possible. Performance records on the strips and streets of America bear this out. In 1990 Dave Mackie high-performance heads were on the Easyrider© Streamliner when it became the World's Fastest Motorcycle at 322+ MPH. Dave Mackie Engineering headwork was a key component in Bob "Rat" Taft's Harley-Davidson powered motorcycle when it became the world's "First 8-Second Evolution Harley-Davidson Motorcycle" powered by gasoline.

Headwork
Valve Job Only: Includes complete high-performance valve job, setup, and assembly. Prices for cam with extreme lifts may be higher - contact us for details.

Porting Only: Includes compete porting and contouring, polishing of the combustion chambers/exhaust ports, and high atomization intake ports.

Complete Headwork: Includes porting, contouring, flow-testing, complete high-performance valve job and assembly (less rocker arms).

Separately provided services include:

  • Cylinder boring and honing
  • Replace valve seats (for use with leaded or lead-free gasoline)
  • Counter bore for Big-Bore cylinders
  • Dual-plug Shovelheads
  • Dual-plug Sportsters
  • Dual-plug Evolutions
  • Head surfacing
  • Compression Releases

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No portion of this website may be published, displayed, reproduced or in any way
disseminated without express written permission of Dave Mackie Engineering

Some parts and services may not be legal on 1978 and later emission-controlled vehicles. Check your local, state and federal laws.*
*Dave Mackie Engineering high-performance headwork and camshafts are not legal in the state of California for use on 1978 and later emission-controlled vehicles.