How can something as simple as a muffler be so complicated? I guess that's what makes these projects so much "fun." I've read all the messages on this but will pose the question anyway. All I want to do is replace the original crossflow muffler with another crossflow muffler sounding a little more aggressive. I have a stock engine and exhaust manifold and stock pipes with a standard crossflow muffler on a 1969 Convertible. I want to retain the single transverse-mounted crossflow muffler setup, but add some mild "rumble" and a "muscle car" sound on acceleration. I also want to exit with a non-spec 2.5-inch slash cut chrome extension (wider than the pipes coming up to the muffler)tucked up tight against the rear valance/bumper. Is the Flowmaster crossflow suitable or will that make the ever-so-common "boombox" sound like my teenager's Bronco? This is a Convertible...I want to be able to carry on a bit of a conversation at cruising speed, or listen to the radio, without that reverberating Flowmaster sound. Any ideas? Do you think the Flowmaster might yet work if I add an X-pipe underneath to quiet the sound a little and use some spacers on the 'Vert X-brace to allow clearance? Thanks.

i have that system on my Nova with an X pipe, and it is pretty mellow as you go down the road. still kinda loud, but bearable. i have 3.70 gears, so at 60, i am cranking out 2800 rpms- if you have different gears like 3.08's or so or an overdrive tranny, it would be really mellow.

I have 3.73 gears. If there is any other brand of crossflow muffler that might work, please let me know. Otherwise, I guess I'll try the above combo and hope for the best.

You might do some research on Edelbrock p/n 5512. I've never listened to one, so I don't know how loud it is.

If you're like me, you probably never drive with the top up. I don't think reverb is an issue in a convert with the top down. I was running a muffler shop dual crossflow and it was never a problem. Good luck!

If you are running a stock or near stock engine then it will be pretty quiet, but more aggressive sounding, with a flowmaster crossflow muffler. I am using the whole force II exhaust system on my nova (with the crossflow muffler) with bigger than stock pipes, and a pretty strong 388 small block backed by 3.73 gears. It is very quiet in the car even at a 3500 rpm cruise down the highway. It is pretty aggressive sounding behind the car (tails exit straight out under the back bumper), but inside it is quiet at any speed. I also have a h-pipe on my exhaust, which quiets them down quite a bit.

Thanks for the Edelbrock suggestion BPOS. I rarely drive this car with the top up...it's a weekend driver with the top down. I'm going to try the Edelbrock...I'll report back on the results.