Convert flow#'s from 4" bore to 3.90 Bore. Possible?
12-17-2004, 06:54 PM
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Convert flow#'s from 4" bore to 3.90 Bore. Possible? I have a set of heads that were flowed on a 4" bore. Is there a conversion factor that can be applied to tell what they would flow at 3.90" (stock bore size)? Am I correct in saying they would flow slightly less on the smaller bore?
Thanks.
Thanks.
12-17-2004, 08:04 PM
#2
Slightly less, yes. How much less is a variable based on valve size, valve shape, seat profile, bowl and chamber shape. The flow difference is not usually consistent from lift point to lift point. For example, you might see a 10cfm difference at .250" lift and 6cfm difference at .400" lift. The percentages are a better indicator than the raw cfm numbers.
I hope this helps.
Good luck,
Richard
I hope this helps.
Good luck,
Richard
12-17-2004, 08:27 PM
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From what your saying, the only way to know what they flow across the range, is to have them flowed on the proper bore size. I knew the numbers were just too good for the work that has been done to these heads. A correction of 10CFM would at least put them in the range of believability. I guess the "Do it right, or do it twice. " rule applies here.
Thanks for the input.
Thanks for the input.