Thats pretty much the question.

My 72 SS Chevelle ran a 12.5 @ 108 mph, while it was my brothers car, with 2.5" head pipes, and 2.25" tail pipes.

(That was on street radials too.)

Think a switch to 3" is best or should I compromise and go with 3" head pipes into 2.5" tails as so many of my TC buddies have, so I can still use the factory tips, and keep the noise to a low roar ?

Also whats the quietest 3 inch muffler any of you guys have used ?

Thanks Thad

By far the quietest performance muffler is the Dynomax Hemi Turbo (20" case). I have these in 2-1/2" version, you can here the rear whining running down the highway.

I had 2.5 through turbo mufflers and 2.5 out behind the tires. I now have 3 inch through an X-pipe thru 2 chamber flowmasters and then 2.5 out behind the tires. I don't know where I got the most gain but it made a hell of a big difference, opened it up and let it breath. Worked great for my application. Which is a stock Ram Jet 502 w/headers/turbo 400/posi-trac rear axle. All in a 1972 El Camino. Not a race vehicle but don't under estimate it...... :D

I would go with the 3" Jegs system and Summit turbos
I went from 2" tails to 2.5" mandrel bent tails and the exhaust got a lot louder running the same mufflers and 2.5" leadpipes.

yes! dynomax super turbos!

the first day i have it on and drive it... wow... quiet, but have a nice sound when i hammer it! just smiley smiley smiley. cant say the same for my petejackson geardrive!

Or Magnaflow #12758.