I am wanting to put a new muffler with a little more sound on my 90 model 3.9, and I was wondering what size the inlet and outlet need to be on my new one when I buy it. I tried searching but I couldnt find the answer. Any help would be appreciated. Thanks

 

most trucks have a 2 1/4 or 2 1/2 pipe or just measure ur tail pipe, id go with a flowmaster real deep sound but pricy or a glass pack if u want it to crackle, cheap,

 

I dont like glass packs. I want a low sound and not really loud just a little more sound than the stock muffler. I was thinking about putting a thrush turbo on it. Its cheap but I dont know what it will sound like on my truck.

 

NO. Not a Thrush Turbo. Those are some of the worst flowing mufflers made. The last time I saw one of those on a vehicle, the muffler itself was literally bloated from the pressure inside of it. If anything, go with the Thrush Welded. Its just as cheap, but flows better and sounded pretty good on my old 02 Blazer with the cat still on.

 

ok thanks i will keep that in mind. now I just got to measure my tailpipe and find out if its 2 1/2" or 2 1/4". I was lookin at the welded too and also the cherry bomb muffler(not the glass pack)..

 

I had a Flowmaster 40 series and it sounded okay. I was disappointed that it rusted away after only 4 years (no winter driving either). I got a Magnaflow stainless muffler (http://www.summitracing.com/parts/MPE-14326/) and I like it a lot better. It's actually quieter at idle but sounds awesome at 1000-3000 rpm.