ACP Headers | Harrisburg, PA | 717-232-2800
ACP Headers will continue Building top quality race headers, parts, and accessories in Harrisburg, PA.
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I believe they are 2" and from a general consensus I have heard on various forums. rob low end torque.. I think Teahead is right on mayne 1 5/8 at most. They won't do much for a stock motor and are, rather. eye candyPretty sure you can still get Stahl headers.
For a stock motor, I would think 1 3/8" or 1 1/2" should good.
-r