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Got a simple question about exhaust pipes and headers measurement.
When one speaks of 2 , 2.5 or 3 inch exhaust etc.., is this size the OD (outside diameter) or ID (inside diameter) measurement?
I am measuring headers and the header collector is 3 inch OD, not ID.
The headers were advertised as 3 inch collectors.
Thanks,
Rule of thumb on header is bigger CI bigger headers. SB 2.5, BB 3". most give OD I believe. also unless your motor is super modified keep you exhaust pipes in the 2.25- 2.5 area or you will loose power with not enough back pressure.
Hope that helps
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Originally Posted by sniperdiver37
Rule of thumb on header is bigger CI bigger headers. SB 2.5, BB 3". most give OD I believe. also unless your motor is super modified keep you exhaust pipes in the 2.25- 2.5 area or you will loose power with not enough back pressure.
Hope that helps
Good grief. Will this old wive's tale never die?????