just installed a gm crate 350 need muffler selection help
 

I have a 1984 chevy sliverado which i drive daily.

the original 305ci (110,000 miles) was showing its age. And i need more pulling power to pull my tractor every once in a while.

Jegs had a new gm 350 crate motor for $1500 bucks, I figured thats a cheap way to keep the truck rolling with more pulling power.

suppose to make 260hp and 350 lbs-tq with headers and 4bb carb.

So i have some 1-5/8 hookers i bought 6 months back for either one of my trucks. Bought them off a guy at the drag strip, a fair deal for almost new.

i have some summit 3" race mufflers (free mufflers) coming off of 1 foot of pipe just to break in the motor and get the truck to the exhaust shop. (freaking too loud)

Plan on doing 2.5" from the headers all the way out the back.

I want something thats quiet but has a little sound. I was looking at some long case magnaflows and the walker quiet flows.

I dont want any interior noise, just would like to hear a little bit of tone.

also i would like it to be quiet while crusin the highway. I probably will do some dynomat in the interior later on.

Any suggestions or experience with the mufflers I listed?

Re: just installed a gm crate 350 need muffler selection help
 

I'm a Magnaflow man myself. Never had any noise complaints but they will talk a little when you ask them to.

Now, another whole can of worms, but in my opinion that combo would be happier with 2.25 inch exhaust. Lots of nice bottom end pulling torque to lug that tractor around.

Re: just installed a gm crate 350 need muffler selection help
 

Go with a 20" body Magnaflow. Dual for a little more noise. I run two 14" Magnaflows on my truck. Go to my videos to hear sound clips. I get compliments all the time. Idle and low cruise sound great.

Re: just installed a gm crate 350 need muffler selection help
 

I like Dynomax super Turbo mufflers

Re: just installed a gm crate 350 need muffler selection help
 

On mine I used a Dynomax Header Back Dual Exhaust Kit (89004) and then Dynomax Ultraflow SS Mufflers (17282). I have had magnaflows in the past and did not want this truck to be as loud (guess I am getting old).

I am happy with the Dynomax and they open up pretty good when you get into the pedal.

You will most likely need to get a muffler shop to bend the front collector pipe to match your headers (I am using Hedman long tubes).

Re: just installed a gm crate 350 need muffler selection help
 

Another vote for MagnaFlows. Flowmasters sound like canned farts to me.I currently have flowmasters on the truck I am building, but as soon as it;s done, they are coming off in favor of MagnaFlows!...oh and I have to agree TOTALLY with Kevin on the 2.25" recommendation!

Re: just installed a gm crate 350 need muffler selection help
 

So what's up with the 2.25" pipes vs 2.5" pipes? What makes it better?

Re: just installed a gm crate 350 need muffler selection help
 

2.25 is stock and is all it needs unless you are going for much higher horsepower engine build. With just the goodwrench 350 it is a good match.

You also need to remember you need back pressure which keeps the torque numbers up and if you are like me your emissions stuff like the cats are long gone.

Re: just installed a gm crate 350 need muffler selection help
 

I run the large case Dynomax Super Hemi Turbo mufflers with 2.25 pipes.

Very mellow, no drone....maybe too mellow for some but, just right for me.

Re: just installed a gm crate 350 need muffler selection help
 

I believe that it's more "proper scavenging" that you need, not back pressure. Too large a pipe, and the exiting exhaust kinda gets lost and does not help draw the next exhaust pulse out of the cylinder.

Smooth flowing pipe (ie: mandrel bends) will help the exiting exhaust continue without slowing down too much, whereas tight restrictive bends will slow the exhaust down and reduce the scavenging.

The only time you need bigger pipe is if you're moving ~more~ air. A "volume" issue.

David Vizard has a lot of cool articles out there on exhaust, sound, and making power.

Re: just installed a gm crate 350 need muffler selection help
 

FWIW I have some Raptor mufflers on my truck with 350, headers and 2 1/4 pipes. They are very quiet at idle and in the cab but they have a nice bark when I get on it. I was going to change them because they were too quiet but now I like them.

Re: just installed a gm crate 350 need muffler selection help
 

both Jimmys have 2.25 pipes,out before rear wheels
K78 true duals (aftermarket walker pipes) to Cherry bombs
C79 true duals,H pipe,custom bent to Flowmasters