Cylinder head porting
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Cylinder head porting refers to the process of modifying the intake and exhaust ports of an internal combustion engine to improve their air flow. Cylinder heads, as manufactured, are usually suboptimal for racing applications due to being designed for maximum durability. Ports can be modified for maximum power, minimum fuel consumption, or a combination of the two, and the power delivery characteristics can be changed to suit a particular application.
A mold of the suboptimally designed ports of a Ford two-liter head for use in Formula 2000 racing. It is shown as manufactured with the intake port on the right.
Port molds of a highly developed 500 cubic inch aftermarket Pro Stock racing head. Note the height and straightness of the ports, particularly the exhaust port on the left. This design is based on a cylinder head casting purpose-built for racing modifications. The head is supplied with small ports with ample material everywhere for porting specialists to shape to their requirements without having to weld on additional metal.
Rotary tool
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A die grinder or rotary tool is a handheld power tool and multitool used for grinding, sanding, honing, polishing, or machining material. All such tools are conceptually similar, with no bright dividing line between die grinders and rotary tools, although the die grinder name tends to be used for pneumatically driven heavy-duty versions whereas the rotary tool name tends to be used for electric lighter-duty versions. Flexible shaft drive versions also exist.
A pneumatic die grinder with a right-angle head.
A cordless battery-powered rotary tool used for light tasks.