Know anything about mufflers?

[MarkAd]

Sheepdip, perhaps you should read ALL the posts before making the comment.

all posters here make it sound very simple

I recommended a shop.

Well anyway, your nickname seems about right.

 

[deadshot2]

It would seem that everyone overlooked the OP's original complaint ----- LOUD

All these aftermarket suggestions aren't necessarily known for their Quiet.

 

[orygun]

Sounds to me like the muffler on the truck now is failing from the "inside out" like someone else commented.
1970 Blazer 350 2 1/2" in-2" out sounds like bone stock to me. 2" tailpipes, even on V8 cars and trucks was very common in the 60's and 70's. Remember that stock single exhaust systems were designed to work at typical cruise speeds, not for performance.

Any of you bashing Sheepdip for the prices he mentioned for brand new, full length dual exhaust systems just haven't priced this kind of work recently. IT does seem like a lot of money for what should be a simple job, but that's just the way it is.
I used to work in an exhaust shop as a teenager. It is "simple work" when it's on a rack and you have all of the right equipment, but it's a bubblegum when you are flat on your back and working with minimal tools.

To the OP, if you were happy with how things were before the muffler went bad, go to you local auto parts store and price redoing the needed parts with new, stock items. If you have to replace the exhaust pipe that bolts to the manifolds, be very careful. The GM studs are fairly small and are prone to snapping.

If it was my truck, and I could afford it, I would put on new, full length dual exhaust with a muffler that was not a Flowmaster or a knock off of one. I don't like that much noise on my truck. I would also avoid headers like the plague. Remember, this is a truck, not a Hot Rod, and the true dual exhaust will be a win-win as far as fuel mileage and performance.

 

[Redcap]

Any of you bashing Sheepdip for the prices he mentioned for brand new, full length dual exhaust systems just haven't priced this kind of work recently. IT does seem like a lot of money for what should be a simple job, but that's just the way it is.
I used to work in an exhaust shop as a teenager. It is "simple work" when it's on a rack and you have all of the right equipment, but it's a bubblegum when you are flat on your back and working with minimal tools.

Three weeks ago, I had a headers-back set of pipes (2.5" to the muffs, 3" behind muffs to rear bumper) with H-pipe put on my big-block GMC crew-cab 4x4 at an exhaust shop because I was crunched for time. I did supply the mufflers, but I got out of the shop for $290 after tax. Figure in the cost of my $60 pair of Summit mufflers and I'm into the whole thing for $350. The place I had it done also wasn't the cheapest one, rather one that was available at the time I needed it.

$500 with your mufflers is ridiculous. Even more ridiculous is adding a set of Flowmasters for an extra $250, since likely we are talking about a set of standard Flowmaster 40s (which are $70 retail...and any shop paying retail prices for materials is doing it wrong).

 

[mjbskwim]

I did my 6" (as in HUGE diesel exhaust) aluminumized exhaust, from my turbo to behind the rear wheel with a muffler (straight thru of course) for $700.
Yes I did install it myself as it was cut and bent perfect for the truck,but the materials for the SIX INCH exhaust were only $700

I have done my own exhaust work for around 35 years.It aint that big of a deal.Fairly easy bubblegum.
Easier if you have a hoist and a nice mandrel bender.

And who the HE!.!. would pay $250 for mufflers? On a chevy?
(as opposed to say an Audi/benz/bimmer)

 

[Bigfoot]

Thanks for the information guys. Now that I know it isn't being caused by backpressure I don't have anything to lose by trying to fix it myself first. This muffler case had been pushed in slightly and it's this weakened spot that flexes (loudly) with the exhaust pulses at idle. I'm going to practice welding on the old muffler, if I can keep from blowing holes in it then I'll weld a strap onto the muffler lengthwise to stiffen up the case or weld a piece of sheet metal onto it and tack the center in several places.

If it still rattles after than then something else is lose inside and I'll cut that POS off and get a new one. I've been laid off a long time now so I'm being even cheaper than normal. I'm still going to buy that new 380 pistol though, I'm not that cheap.

 

[sheepdip]

sounds like the spot welds on the interior of the muffler are broken loose, not much you can do other than replace the muffler