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Old 09-03-2020, 05:45 PM
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ponjohn ponjohn is offline
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Join Date: Mar 2002
Location: Connecticut
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Quote:
Originally Posted by Steve C. View Post
OK, the subject of the KRE head has been brought up. Now relating the difference in intake runner volume between the KRE head and the Edelbrock head. The Edelbrock head having the larger intake runner volume.

I believe it was steve25 years ago that made a statement that one would need more intake duration as the runner volume increased to make the similar amount of power at the same or similar peak power rpm. Or something to that affect.
I don't remember how many degrees increase he mentioned, not much though.

As an example... I have dyno sheets for two different engine combos that are so similar you might say they were the "same". One with unported KRE D-port heads and another with 87cc Edelbrock heads with a slight 'clean up' only, almost stock. Both used Crower hyd flat tappet cams. The KRE combo made 502 hp at 5300 rpm with 231 degrees intake duration. The Edelbrock combo made 509 hp at 5300 rpm and used 236 degrees intake duration. This might support the statement above about runner volume and increased duration.

A fwiw, Tom Schlauch has often reported with his combos that a 455 with KRE 290 D ports, 245 degree intake w/ 252 degree exhaust & .4000" lobe lift hyd roller cam were in the 550-600 HP range depending on intake and carbs.


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KRE has achieved 545 hp with unported d-ports. There are a few dyno sessions shown on FB.