We offer this service in coperation with Hammer Performance
The Impact level is a perfect match for bolt-in cams and street type exhaust systems, giving a wide powerband and a smooth running engine, with the reliability and longevity you demand.
We start by stripping down your heads, cleaning them thoroughly, and inspecting them for any defects.
We then run them through our exclusive 4-Axis CNC porting process which sizes and shapes the ports for maximum torque over a wide rpm range. The CNC machine is also used to open up the seat diameters and rough in the valve job. A hand finishing process is then applied to the ports and bowls which basically compensates for variances in castings.
Next, new bronze manganese guides are carefully pressed-in and sized followed by an exclusive radius valve job on the seats, paying special attention to the target stem protrusion and resultant spring installed height. We reface your valves, lap them into the seats, and despite the incredible repeatability of the CNC process, we flow test every head as a quality check.
Your heads are then decked for a perfectly flat gasket surface and to size the chamber back to factory specs.
Finally, we test your springs for proper seat pressure and travel, and assemble the heads with new high-temperature viton stem seals.
The end result is a set of heads that are better-than-new. They will tremendously outperform the stock heads and can take much better advantage of your performance cams and exhaust system.
We've had numerous customers break 100rwhp using this level of head prep on their Sportster or Buell. It's a truly a superb performance value.