Re: Port match or not
The link below is to a post I just put up today on the FE Forum. In the case of this engine, a Victor intake port matched to the heads was worth between 20 and 25 HP over another Victor with just the baseline 427 medium riser ports. This is a pretty extreme example, because the difference in port sizes was about 0.200" in both directions, but in general on FEs I've found during my dyno testing that matching the ports between the intake manifold and the head is usually worth 5-10 HP, with no appreciable loss in torque. One of the real interesting ones I tested was the Performer RPM, which didn't fit this general rule; here the as-cast manifold outperformed the port matched manifold in torque by about 10 ft-lbs on a 500 HP engine, but was down about 7 HP compared to the port matched intake. Kind of a toss up on whether or not to port match that one.
I think FEs may be more sensitive to this issue as compared to other engines, because the pushrods go through the intake manifold rather than the head. As a result the pinch point between the pushrods is in the intake manifold. A good port match will extend a couple inches up into the port and clean up the port between the pushrods, leading to some benefits that may not be found with intakes for other engines.
The link below is to a post I just put up today on the FE Forum. In the case of this engine, a Victor intake port matched to the heads was worth between 20 and 25 HP over another Victor with just the baseline 427 medium riser ports. This is a pretty extreme example, because the difference in port sizes was about 0.200" in both directions, but in general on FEs I've found during my dyno testing that matching the ports between the intake manifold and the head is usually worth 5-10 HP, with no appreciable loss in torque. One of the real interesting ones I tested was the Performer RPM, which didn't fit this general rule; here the as-cast manifold outperformed the port matched manifold in torque by about 10 ft-lbs on a 500 HP engine, but was down about 7 HP compared to the port matched intake. Kind of a toss up on whether or not to port match that one.
I think FEs may be more sensitive to this issue as compared to other engines, because the pushrods go through the intake manifold rather than the head. As a result the pinch point between the pushrods is in the intake manifold. A good port match will extend a couple inches up into the port and clean up the port between the pushrods, leading to some benefits that may not be found with intakes for other engines.
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