Jim Smart
November 29, 2006

Affordable Port Work
Affordable factory head porting is available from PowerHeads in Southern California. PowerHeads uses CNC technology to hog out the intake and exhaust ports on 260, 289, 302, and 351W heads to make them one of the greatest performance values in the industry. For under $1,000, PowerHeads takes your cylinder-head castings and after CNC-port work along with hand-massaging finish work, vastly improves performance. PowerHeads will install your valve springs at the same time. You can provide the head cores or PowerHeads can provide them. The choice is yours. If you want your cylinder heads ported and returned to you, please advise PowerHeads and document your request. If you don't, expect a different set of heads.

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Here's another example of core shift during the casting process that causes exhaust-port irregularities. PowerHeads has worked this port as much as it can. This is why proper head selection is so important to good porting.

Wild, Weird Science
The science of port work is little more than common sense. Think of the flow of air and fuel as water. Water ripples and aerates as it cruises over surfaces. So do air and fuel droplets. Our objectives are smooth surfaces and turns. We want increased velocity while we're at it. Velocity is simply air speed, how fast air and fuel move through an intake port. On the exhaust side, we want hot gasses to leave quickly without a traffic jam. We actually want those hot gasses to help with intake flow when we have valve overlap.

Matchmaker, Matchmaker
Intake manifolds and carburetors are just as significant to porting as the human eye and a grinder. Carburetors must match intake manifolds. Intake manifolds must match cylinder heads. When perfectly matched, airflow becomes smooth and plentiful. We cannot overemphasize proper port matching.

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