i see in Jegs that they carry Thrush mufflers. i'm looking for a pair of 3in/out mufflers for my 2500HD to swap in place of the OEM muffler.
the one i'm looking at is PN 289-17657.
anyone know if these are worth it at the $30 price tag?
my other consideration is the Magnaflow 642-12259. they are $87 each.

Those thrush mufflers are the "turbo muffler" style (I used them on my 1977 3/4 ton Chevy). It has two or three louvered passages in them and they flow "ok", but not particularly great. If you are desperate for a muffler, they work (but can be loud). If you're looking for effeciency gains, buy a Dynomax (who makes Thrush) Ultraflow or a Magnaflow "straight through" design. Your other choice is out of stock. Hooker Max Flow also flow well.

What's the goal of this swap Glenn?

i'm just looking to get a increase of power. i don't want it loud. i don't mind it louder, just not 18 year old redneck loud.
my HD 6.0ltr gas is ok w/ the 24' enclosed, but at 10-12K it just works a little harder than i'de like.
i'm also considering a small cam swap too to help it pull better. i don't need it to be wild, just work better. the thrush ones i'm looking at are not the "turbo" ones. these are the fully welded case ones. are they the same?

as a side note, i cant get over how much Flow's cost now.
Magnaflows are the #1 muffler on my list.

I thought those were the "super turbos" for that price. What part number were they? The Edelbrock stuff is nice. The magnaflow "straight through" stuff flows well (I have a 3x9" "race muffler" under the camaro). With full pipes it shouldn't be "too redneck loud", but it will be throaty.

Glenn,

On my HD I'm running this FM, #530504 - http://www.flowmastermufflers.com/products...;keyword=530504

However, I was surprised at the cost myself. I didn't pay near that much when I had it installed four years ago.

I replaced a pair of no-name turbo mufflers that the original owner had installed poorly. I immediately picked up an improvement, as the truck wouldn't turn a tire before. The only downside is the interior resonance at 70 mph and above. My Z with LTs, high-flow cats, and FM is quieter. I did call FM to ask about something quieter but they said because it's an HD with the dual 3" piping that the resonance is just going to be there.

The one time I've experimented with another brand (Midas' Ravin performance muffler) left me speechless at the claims of better HP. All I got was MORE interior resonance and an immediately noticable increase in backpressure

I had an edelbrock cat-back on my z28 and it was junk. The stainless muffler failed (was a crossflow design, blew out the sides of the case!?!) and I picked up noticable HP when I did a Magnaflow straight through muffler single in single out. So far it's been great and not loud at all.

i ordered this one today. i should get in on after Hallett next weekend.
http://www.jegs.com/webapp/wcs/stores/serv...hTerm=642-12599

How do you plan to route the tailpipes? Mine are angled to the corners underneath the bumper. I'm also curious about how much interior resonance you will have. Radioshack sells a hand-held db meter and I've used it to gauge various noise levels when tinkering with exhaust configurations.

Interesting that the Magnaflow is 3" in/out while my FM is 3" in/2.5" out. Another source of restriction...

i plan to find a 2nd OEM rear section and use two OEM rear pipes on the muffler. otherwise, i'll fab my own duals and dump in front of the axle if i have to.

hmm...dumps under the body are very loud...as in "18 year old redneck" loud...highly recommend tailpipes!

yep. there will be lots of road tests and trailer towing tests.

slight hijack - I am now convinced that under most part-throttle situations some sort of header (shorty or LT) actually decreases interior resonance. My next mod to the truck will most likely be some JBA shorties.