I suspect a very low compression engine (403) is more inclined to like minimum back pressure. Mine worked best (didn't try headers) with an exhaust that had almost no measurable back pressure.
Bruce Roe 4 May 2006 "Infinite Space Systems, Inc." <[EMAIL PROTECTED]> writes: > > Not if it's built right.... > > My opinion is you can have too large of a diameter/ freeflowing > > exhaust on an Olds depending on how the motor is built. I ran > > open pipes (cutout before the mufflers) on a mildly built 350 > > and it ran better times and > > pulled better when I ran through the mufflers.
