quiet down drone on 350 with pieced together exhaust

[bcraig350]

I've got a truck with a 350 TBI that's had some custom exhaust work done to it before I bought it. It has everything stock up past the cat, then has a custom fabbed dual exhaust that Y's off behind the cat and runs two 3" pipes with some unknown glasspack mufflers on each pipe which exit parallel to the ground but at a slight angle to the sides (i.e. not quite straight out the back). The truck actually sounds pretty good, IMO. It was a bit loud for just driving around town, not really that bad though, but embarrassing when I was trying to be quiet (driving into neighborhood late at night, etc.) The real problem was the sound at interstate rpm, which I think is what people call "drone." Above 60mph or so, it is loud enough that it leaves your ears ringing after a long drive. It an attempt to help with a cheap solution, I had a muffler shop install a resonator between the cat and the Y-point for the dual mufflers. It helped with the overall loudness a bit without messing with the good sound and it took the edge off the drone, but it is still a bit excessive.

First, is that too much exhaust for the truck, two 3" pipes after the cat? Or does it not matter at that point because the cat is the biggest restriction? What would be a good replacement muffler? I would not mind keeping the two pipes, hence two mufflers, but at this point my primary concern is no drone.

[cancritter]

single 3 inch

[Red91]

My response may not be the cheapest but... My 91 is a TBI 350 I have a factory y-pipe that goes to 3" pipe thru 3" converter then 3" pipe to a 3" in dual 2.5" out Flowmaster 40 then goes to 16" long 3" tips no drone KINDA quiet at idle, real good snort when your on it, no drone on the interstate. Sounds great I love the set up. Sounds more like a muscle car than a truck. My truck is stock other than the pipes and tires. No cam no tune no nothing. http://i1205.photobucket.com/albums/bb438/Red-91/Red%2091/205.jpg Best shot I have of the tips. Hope this helps! Sorry no video.

[Quyonmob]

Single 3" is more than enough for a 5.7L TBI.

IMO, remove the Y, use one of these tailpipes, cut the glasspack out for a real muffler.

[Low97tahoE]

Single 3" is more than enough for a 5.7L TBI.

IMO, remove the Y, use one of these tailpipes, cut the glasspack out for a real muffler.

i second that, get a 14" magnaflow or equivalent, or 18" if u want it fairly quiet

[1ugly88]

my yukon is similar to what you have now. i have the stock y-pipe, no cat, single 3in back to a y, then 2.5 duals to 2 thrush welded mufflers and had the tails turned out behind the rear tires. no drone what so ever at any speed. can barely hear it in the truck when cruising and has a really nice bark when you put your foot down. was kinda disappointed when i first got it back from the shop cause it's so quiet(compared to every other system i've had) but love it now that i've put some miles on it. no more shouting at the person next to me. can actually hear the radio at a decent volume.

[bcraig350]

cool, thanks for the input guys. I think what I might do is stick a good single in/out muffler up behind the cat and then keep the dual pipes and replace the glasspacks with tips. I'm thinking that might allow me to do as little custom work as possible on the system that's already there.