HICKL Posted September 10, 2004 Share Posted September 10, 2004 I bought me a set of Dart II heads and plan to bolt on this weekend. I was looking at the heads and the exaust ports are pretty square. By headers and brass header gaskets are round and thus will have a "lip" at the 4 corners as the air exits the head. Is this pretty typical? Will it have a big impact on airflow/hp? Seems like it would be a major restriction. Quote Link to comment Share on other sites More sharing options...
Guest Aaron Posted September 10, 2004 Share Posted September 10, 2004 My understanding is that as long as the header is as large as or larger in diameter than the port you are good to go. If the header is smaller, you will create a major flow restriction. The effective size of the header will be about 75% of its diameter because of the way air flows into an unradiused opening. Quote Link to comment Share on other sites More sharing options...
HICKL Posted September 10, 2004 Author Share Posted September 10, 2004 Actual volume, the header pipe is probably equal or bigger, but where the round meets the square, the corners will see bit of a shoulder Quote Link to comment Share on other sites More sharing options...
Sleeper-Z Posted September 11, 2004 Share Posted September 11, 2004 if you're worried about it, get the ol die grinder or dremel and do a port on the corners and edge em in. that's 'if' you have enough meat to port. glad to hear you got some heads. -steven m. Quote Link to comment Share on other sites More sharing options...
jt1 Posted September 13, 2004 Share Posted September 13, 2004 There is some flow restriction there, but as a practical matter the effect is pretty small and would only be noticable on a back to back dyno comparison, maybe 5 or 10 hp at the most. Getting the headers to seal to the heads may be a bigger problem, sometimes when the port shape is different the gaskets don't have much sealing/clamping area and give problems leaking. John Quote Link to comment Share on other sites More sharing options...
HICKL Posted September 13, 2004 Author Share Posted September 13, 2004 I went ahead and put it together as is, wasn't that bad. Hey Sleeper, when can I get that cowl hood from you! With the heads, I need a taller intake for some flow. If you ever decide to sell it let me know. Jeff Quote Link to comment Share on other sites More sharing options...
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