Exhaust question

[badmix]

I want to be able to use my rear window, you know, put it down, without killing myself from fumes. Ive got 2 1/4 duals running out the back. Ive got 3" collector on my header. What would be the pro and cons of just running 3" single pipe (w/ catco cat and flowmaster muffler) and exit to the side, behind the rear tire. Is it worth it? What kind of sound would I end up with. Motor is 305cid stock.

 

[George_Pimpdaddy]

well the single 3" is what they came with factory at least on my 89 so id go with it if the fumes are getting to you.

 

[toomany]

I've got my exhaust exting behind the rear tires on each side. I have no issues with fumes getting in, moving or sitting still.

If you plan on running a 3" pipe from each header back...that is way overkill for a stock 305. A y of the two headers into the 3" pipe would be the way to go.

 

[blowedupmotor87]

I have 2.5" (IIRC) from the headers to behind the transfercase where the "Y" comes together into a 3" single with cat and a flowmaster knock off (equivalent to a 40 series IIRC), exiting behind the rear driver's side tire. I can't comment on fumes but, the sound (stock 350) is great! Nice and rumbly, sounds like a muscle car! I could wish it was a little quieter for crawling though (makes it a little hard to hear a spotter).

 

[Slapperbar]

Sounds like you are doing what I did. The 3" American Thunder (I think) sounds great with the high flow cat. Nice rumble and not too loud.

 

[diablo1]

My duals are straight out the back and the fumes are killing me. Running them out the side is really that effective?

 

[toomany]

My duals are straight out the back and the fumes are killing me. Running them out the side is really that effective?

Yes

The air behind the truck is a negative pressure when moving. When the window is down the air/exhaust gets sucked back into the truck. If the exhaust exits to the side, it won't/it's harder for it to come back into the window. I've heard having one of thoes spoilers on the top can help with this.

 

[loudnslow]

I'm in the same boat with a 350 though. The current exhaust has way too many holes and longtubes are sitting in the garage.
After reading around here I'm planning on 3" ypipe, no cat and exit behind rear tire.

What would you guys recommend for quiet yet free flowing and no cackling muffler?