George's headers:
https://www.gt-racing.com/products-page/911-exhaust-systems/headers-for-911-2-7-3-2-liter-motors-with-street-adaptor/
Quote:
|
-These headers measure 1 5/8" O.D and 38MM I.D.
|
Buckley Racing:
Buckley Racing - 911 Racing Headers
Quote:
|
Step design, 1 .625” OD primary tubes stepping to 1.75” OD.
|
The only thing I can figure is the step to a larger diameter in the Buckley's (
about mid-way?) slows the travel rate of the exhaust on stock/lower powered engines.
Buckley Racing - 911 Racing Headers
Bigger pipes are not better, often you will lose low and mid band torque (
from what I've read).
The Buckley's seem to be longer than the George's, typically meaning more low/mid torque for the longer Buckley headers. However, they may be slowing the gasses down with that step, which is great for 400 hp engines requiring that mass flow of volume, not so great for 200 hp engines which cannot push so much exhaust.
http://www.buckley-racing.com/911racingheaders.html
EDIT:
I could not find the diameter of the George's street adapter which is after the 3:1 collector, but it's an apple & oranges thing as they are two different header designs.