ok i am new here and i need lots of help. i have seen the light and 3rd gen rules. i will admit i used to have a rustang. but anyways, i am having a hard time trying to find someone who knows if i can run full length headers on my car and true duals with the mufflers dumped under my seat. or if i have to go with shorties and run a y pipe. if i run a y pipe i want to run it into a 3" pipe and stop it just short of my rear end. please help me here fellas i am new to this and if u could please read my other postings which i need much help in also. thanks

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1988 firebird formula350 msd 6al box blaster 3 coil accel 8.8 wires flowmaster cat back pro shift light a pillar gauge pod and water temp and air/fuel ratio gauges b&m mega console shifter

 

Third Gens sit so low stock that it is virtually impossible to put a muffler anywhere except the stock location. For the same reason, you have to run headers that are specifically designed for Third Gens.
I saw a tbi car a couple of weeks ago that had the exhaust pipe running down the center of the car along side of the drive shaft. I think with a set up like that, you could run true duals down the entire length of the car, and then use a pair of the short Flowmasters or something similar going to away from each other to exit at both sides of the back of the car. The other possibility would be to run 2 pipes all of the way back down the passenger side of the car where the existing pipes are, and then fit 2 small mufflers in the space where the stock car has one.

 

One more thing. No matter what sort of exhaust system you run, you still want some sort of crossover pipe between the dual exhausts to help scavenge #5 and #7 cylinders.

 

ok this may sound dumb but my muffler shop here in town already told me if i brought my are in with out the cat and headers on he would weld up what ever i wanted done. now what is a cross over pipe? i have seen plenty of 3rd gens with duals and long tube headers i just wonder how do they do it? and if possible what part number long tubes could be and the manufacture. also i do plan on running either 1 chamber flowmasters or a muffler have seen but not heard spintech

 

I saw an IROC last week that had duals on it with the pipes exiting in front of the rear tires.Sounded great but I'll bet he has to avoid all railroad tracks,and speed bumps.

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We need Perry Mason

 

Howdy there, I have an 85 SC and with my 350, I'm running dual exhaust right now. No computer or cat or any such thing, simply Stan's custom 1 5/8 Tri-Y headers, which are full length and end just shy of the tranny X-Member, then 2 1/2 inch pipes down either side of the drive shaft, over the axle, then crossing from one side of the car to the other through glass packs that are side by side in the stock muffler location, then exiting on the opposite side of the car straight back from where the main pipe ran down the driveshaft. FYI, I have little to no ground clearance and the pipes show it in a big way by the cross member do to home-made speed bumps here in Montana, and where the pipe crosses over the axle on the driver side in the rear the panhard rod has a tendency to strike it during big bumps even though it's been flattened to an oval shape as much as is possible. The exhaust sounds goddamned good, but it's loud all the time hence the glasspacks. I've had nothing but problems with ground clearance and various welds breaking do to the lack of clearance. Where the pipes run under the X-member it tends to rattle a bit. Power and sound is fine, I love the headers but wouldn't reccommend such a set up for anything other than drag racing where drive-ability is at a minimum. I am now changing over to SLP exhaust, have the 1 3/4 header's already and am saving for everything else while I purchase various other things and plot and plan head and intake changes. Oh, FYI, I am doing a complete GLobal West suspension, and with the exception of Sensa Trac shocks and struts, and stock torque arm I'm damned near there. Hope this helped you all somewhat, but like I said I'm tired of it and going with the SLP 1 3/4 with a Three in Catless back exhaust..LOL All I'll have to do is make an intermediate pipe in place of the Cat. Any questions, concerns, or comments feel free to ask. TAke care now...

 

i had true duals on my car before the 355 and it was ok except for the trans x-member make sure you have plenty of clearence in that area also i had tailpipes made for mine come emissions time my mufflers sat in front of the rear end kinda like a stang. that was with shorty hooker headers. but now i have a single 3" with a custom ypipe similar to the new LS-1 cars....good luck either choice will work it up to you...the single 3" is more unassuming to the competition..he he

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87GTA 355TPI,A4 shooting
for low 12'

 

i ran daul exaust on my car and i think it sucks a$$ yes it sounds great but you almost have to run the 2 pipes side by side down the passenger side of the car and the 2 pipes will hit the bar that ties the frome work in the back of the car to gether. i have my muffler right where the cat use to be and i had i weld brake that held the 2 pipes together now they rattle i need to reweld... any ways i would go with a single exaust flow master american thnder exaust systems sound great.

 

Welcome, search the exhaust board for fast3rdgen's setup.

This is what I'm doing, except I'll be using coated hedman long tubes, then the S extensions into dual 2.5'' pipes.

 

Yup, I'm goin with just an H pipe, I can't see spendin 3x the amt to get an X pipe.

 

i like the y-pipe with 3 inch intermediate pipe..