Mega-Sphere™ Squish Head and Piston Design
Dave Mackie Engineering provides its revolutionary Mega-Sphere™ Head and Piston design for both Evolution and Twin-Cam motors. Take your pick:

The Mega-Sphere™ for Evolution Motors
The Mega-Sphere™ is a dual-squish head and piston design from Dave Mackie Engineering (DME). The piston itself is a DME/JE 30° full-dome piston which is dished in the center. The piston dish and the shape of the head combine to form a near spherical combustion chamber at top dead center. The dual-squish band is created by machining the stock flat squish of the head to an angle slightly greater than 30°. This forms a megaphone or wedge-shaped squish band. This Mega-Squish™ design forces the fuel/air mixture toward the spark plug and up into the sphere rather than forcing some mixture forward and the rest sideways or backwards like a flat/parallel squish band does. The result is the most efficient combustion chamber for complete burning of the fuel/air mixture which means maximum power and economy.

Cylinder work done at DME uses state-of-the-art boring and honing equipment and techniques worthy of these great pistons. The cylinders, complete with gaskets, are torqued between specially designed torque plates and heated to operating temperature to simulate engine operating conditions. This procedure allows the cylinders to take the set they will have when installed on the engine. After cooling they are given a multi-level cross-hatch pattern that is best for the application and finished off with the latest plateau honing techniques as recommended by ring and piston manufacturers.

The heart of the package is DME headwork, which for decades has been ranked with the absolute best in the industry. Headwork is port, polish, contour, flow, competition valve job, and assembly using all premium parts including a titanium collar, thermal-coated spring kit.

The final part in this potent DME package is a DM580 camshaft set. The lift of .580 is enough to fully extract the tremendous flow and velocity potential of the heads, which produces great power with little or no valve train noise. The event timing and overlap characteristics make this cam a torque animal from just off idle. It pulls like a freight train all the way past 6000 RPM. The final result of this DME combination is a very streetable bike with the best overall blend of torque and horsepower available. Power is in the 85-95 horsepower range with 85-95 pounds of torque. The actual power you experience will depend on the total combination you put together. Carburetion, ignition, exhaust system, and how well the bike is tuned will all have an effect on power output.

The kit includes complete headwork using all premium parts, boring and honing cylinders, pistons, pins, clips, rings and DM580 camshaft. Suggested Retail: $1,670.00.

The Mega-Sphere™ for Twin-Cam Motors
The Mega-Sphere™ is a 360° squish head and piston design from Dave Mackie Engineering. The piston itself is a DME/JE 20° full-dome big bore (3-7/8) piston which is dished in the center. The piston dish and the shape of the head combine to form a near spherical combustion chamber at top dead center. The 360-degree squish band is created by machining the stock flat squish of the head to an angle slightly greater than 20°. This forms a megaphone-shaped squish band. This Mega-Squish™ design forces the fuel/air mixture toward the spark plug and up into the sphere rather than forcing some mixture forward and the rest sideways or backwards like a flat/parallel squish band does. The result is the most efficient combustion chamber for complete burning of the fuel/air mixture, which means maximum power and economy.

Cylinder work done at DME uses state-of-the-art boring and honing equipment and techniques worthy of these great pistons. The cylinders, complete with gaskets, are torqued between specially designed torque plates and heated to operating temperatures to simulate engine operating conditions. This procedure allows the cylinders to take the set they will have when installed on the engine. After cooling they are given a multi-level cross-hatch pattern that is best for the application and finished off with the latest plateau honing techniques as recommended by ring and piston manufacturers.

The heart of the package is DME headwork, which for decades has been ranked with the absolute best in the industry. Headwork is port, polish, contour, flow, competition valve job, setup and assembly using all premium parts including a titanium collar, thermal-coated high-performance spring kit.

The final part of this potent DME package is a TC590 camshaft set. The lift of .590 is enough to fully extract the tremendous flow and velocity potential of the heads, which produces great power with little or no valve train noise. The event timing and overlap characteristics make this cam a torque animal from just off idle. It pulls like a freight train all the way past 6000 RPM. The final result of this DME combination is a very streetable bike with the best overall blend of torque and horsepower available. Power is in the 100-115 horsepower range with 105-115 pounds of torque. The actual power you experience will depend on the total combination you put together. Carburetion, ignition, exhaust system and how well the bike is tuned will all have an effect on power output.

The kit includes complete headwork using all premium parts, boring and honing cylinders, pistons, pins, clips, rings, and Twin-Cam cam set with new bearings. Suggested Retail: $1,835.00. Also can be had with gear drive cams: Suggested Retail: $2,225.00.