ATM, I have shorty headers on my car with 2.5in y-pipe and a 3in cat back exhaust with dual tips. my car is a 85 z/28 with a 5.7 TPI swap

I want dual exhuast, but the tunnel system is crappy setup lol.
My plan is to do 2.5 in pipe off the headers straight back through cats w/o mufflers and dump straight down in front of the axle(about under the rear seats)

has anyone ever done this? and is it a major clearance issue? I don't think it would be and I know a shop that would do it. I have heard a 305 bird with TBI and it isn't astronomically loud so I don't think sound is too big an issue,
fumes maybe but im not too worried about that I have my fan and that will blow most of them away from the car

thanks for the info

 

its been done before. you dont have room for the tubes - they will bump everytime you have a dip in the road.
and dumping exhaust under your car where it can come back up if you are sitting in traffic is never a good idea.
what you are talking is old world duals we used to put on 55-65's. they had plenty of room under the car which also means they air did not come back up into the passenger compartment. plus we always raised the cars rather than lower them.
run true duals if you want but run the exhaust out from under the car - on the side or the back.

 

have to agree w/above post, you do that and you are not gonna like it...

 

Yeah I went out to some shops and talked to them and and exhaust guy where I could really see under the car and thats really all I can do there isnt much clearence thanks though!