The flowmaster site does explain it in their FAQ...about thre fifth or sixth question. You can buy their muffler technology which is explained also based on how aggressive the sound is...series 40 is the most aggressive and does have the drone at two rpm ranges....and what I have. I'm not sure how the other modern muffler systems work but suspect they are more on using physics as well to manage the sound rather than just packing to absorb it.

Here it is if you want more info on Flowmasters:

http://www.flowmastermufflers.com/index.php?page=40

 

sakins...one of the vendors makes a bracket that bolts to the cross member that the pipe comes through instead of that frame part the u bolt is tightened against with the pipe. the bracket has rubber between the fastening to the cross member and the u clamp that holds the pipe in the center of the hole through the cross member. If I understand your photo right it looks like someone jury, rigged an attachment point and does not match anything I saw anywhere. Just about every bracket mounted wherever has a bracket to attach and some form of rubber or material that is flexible and allows small amounts of controlled movement and not metallic to deaden sound transfer also..... between it and the holder around the exhaust pipe. If you bolt that pipe firmly to any frame member then any sound in the pipe will tend to make the frame member resonate with it and transfer both heat and sound wherever that frame member goes. If it's not fastened tightly it will rattle. if it's fastened tightly it will likely resonate. I had a broken hanger behind the cross member on tired and exhausted pipes and they let the pipe rest on the cross member and the weight over time contributed stress to the exhaust manifold and was a factor in cracking it...all done by the p.o. and I knew I was going to convert it the first year to duals and clean the mess up.

lance

 

Corvette Central Exhaust.com has these parts. They are drilled and tapped for bolts to the cross member, bolts go through isolating rubber and they fit horizontally behind the member centering the pipe as it comes out of the cross member. This is one way to do it without the dual front of the member bracket which is the traditional way. In your case if you have drill and tap this might be better to eliminate your contact in your photo. The brackets for the 2-1-2 looked different for me than for a two pipe straight back dual and I would have had to buy the 2 bracket for the front or these for the back of that cross member.

http://www.corvettecentralexhaust.co...mance_dual.php

Look under performance and go from there.

Hope it helps. I looked everywhere first then ended up having a custom system built and they chose to use rubber isolated j hangers which they could mount and weld in place anywhere so hangers become moot points but you do the whole system that way usually. Mine is welded but with one slip joint in each side to remove if need be(like to pull the differential and put new side yoke axles in). I also used doublewalled heavy steel tube and painted it with vht silver paint.

Lance

 

Thanks for the info Lance. I'll check it out.

 

since i bought my 75, I knew it had some sort of ehaust leaks, but i could never figure out where.

So today my nephew bobby and I replaced the exhaust(pipes only) with a dual magnaflow system from CCE, that's a very nice kit, and easy too.

after taking off all the pipes, we found all kinds of holes and cracks in the pipes from front to back,
and while laying under the car, Bobby saw cracks in the exhaust manifolds too.
He even mentioned that it's pretty common in those manifolds.

So after replacing the pipes, it got rid of a lot of noise, but I can still hear a small tick coming from the manifold leak.
I'm going to look into a new set later.

I haven'y driven it enough yet to norice any droning, but if it does, I'm adding a X pipe.