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Old 08-20-2012, 02:32 AM
FmrStrtracer FmrStrtracer is offline
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Originally Posted by dave350v8 View Post
Thanks for very helpful link,pipe threads are so confusing!
Pipe sizes are measured according to the inside diameter of the pipe(so proper flow can be calculated to achieve the desired flow), so the thread size will always be larger than the pipe size.

GM used at least 2 different size holes over the years, as mentioned above yours sound like they are 1/4 NPT
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