Hand Ported or CNC Ported Heads? You decide.

[Power Ported Performance]

A set of hand ported heads can look impressive. But from a manufacturing stand point, it is impossible to identically size each port volume, or to accurately replicate an "ideal" port design on another head. It is also time-consuming—inefficient for a high variety, low volume porting business. From a performance stand point, cleaning up ports by hand does assist flow by reducing restrictions, but the head can't deliver its full potential because of mismatched port volumes.

By CNC porting the cylinder heads the CNC porting is more consistent and will produce better results. Each CNC ported cylinder head will have the exact same port and chamber configuration as the original master used to develop the CNC program. Following porting each head receives: Precision valve job to maximize flow & provide extended life, milling to ensure deck flatness and correct RA finish for Cometic/MLS gaskets, professional assembly, setting spring height & checking all tolerances.

Hand Porting cannot match port consistency from port to port much less from one head to another. With inconsistency from port to port, the cross sectional area will be different as well and this can be harmful to performance. The bumps in the CNC head are in fact there on purpose, its called a step-over. The step-over can be increased or decreased based on cylinder head design. All of our valve jobs are hand-blended from the seat to the port. Our cnc heads will give consistent results from one car to another to insure that all customers receive the same proven power combination. Also remember, all of our heads are essentially a hand ported head as we started the process by hand porting to find the best possible configuration and once we achieve that, the port is digitized and replicated many times over.

A multi angle valve job, narrowed seats, some detailed work to assist flow around the valve guide boss, blending out any edges in the valve pocket and valve seat areas, and matching the shrouded side of the chamber to the bore generally help with little chance of a negative result. Changing port shape and size without a flow bench and a spare head is fraught with danger.

Polishing the ports will reduce charge temp marginally, but this will have nowhere near as much effect as a gain in airflow.

Polishing the chamber and piston tops can only help, even if for a limited, but is it really worth the cost and time for other than a race engine.

Significant gains in airflow of the port requires changes to many other engine components to optimise it, especially induction and exhaust, but possibly cam and / or displacement.

Unshrouding valves reduces compression, and if this is not corrected, then a net reduction in power might result.