Port Matching the Throttle Body to the Intake Manifold

You can increase the top end HP by porting the lower intake manifold. From the following photo, you can see that there are 4 separate runners for each cylinder. By removing the webbing between the runners, you create a large plenum which improves top end by raising the breathing by about 700 rpm.

Stock 2.3L Intake Manifold

Over at Merkur Encyclopedia, they have two good pages on discussing and porting the 2.3L intake: page 1 and page 2 - both are worth a read. They found that with the stock intake, the top end was limited to about 5500 rpm. With the ported intake, they could go to 6300 rpm. Over at www.ford23.com they have an excellent webpage on porting both types of 2.3l intakes, dual port and 4 port. Good pictures that show the differences.

Here's a video that discusses polishing an intake manifold - not a 2.3L but it gives you an idea on how to do it.

If you want low end power, then you want long runners which means that you don't port the intake. In the early 60s, Chrysler design the Cross Ram intake manifold for their engines to help create low end torque to move the big cars of the day. Those full size cars were weighing in at over 4000 lb!

Chrysler Cross Ram intake manifold with extremely long intake runners

The left side carburator feeds the right side cylinder head and vice versa. The runners were tuned for low end operation. How does this apply to a Ford 2.3L? If you want low end torque for daily driving then you would want each runner to be as long as possible and small. Compare this with the top end performance of the ported intake discussed above. Short runners and a large plenum is used for high rpm performance. Long runners and small plenum is used for low rpm performance.

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Copyright February 2011 Eugene Blanchard