Reply to "Dyno'd the Car, Please Critique."

If you are going to go through the trouble of modifying your headers to add a 3" collector, I would also add 3" ball flanges instead of the standard 3-bolt flange for a leak-free seal without a gasket that blows out. The other advantage is you can reposition the exhaust pipe to center them on the cutout easily. I never liked the Hall Big Bore exhaust because what they called the 'Venturi Effect' collectors which choked their 2.5" collector to a 2" flange. Look at them and you'll see what I mean.

Here's a pic of the ball flange. These are from Flowmaster.



FYI - I have considered 'engineering' a tuned exhaust myself and I gave up after reading up on the theories and applications from better men than I. The best read I have had on exhaust theory were those written by David Vizard.

I made up an exhaust for fun using Flowmaster 40 mufflers (3" single in/ 3" dual out) and they sound great with solid cams. I can really feel them working when I am going through the gears. But, they are loud. I only put them on when I go to the local cruise ins. Attached are pictures of the Flowmasters on my car:




Good luck with your build.