Max

I'm planning to replace my entire exhaust.
Emissions are not an issue. I'm planning on using headmann headers and extensions (instead of the factory type Y pipe setup).
I also want to fabricate an H pipe to equalize the pressure. The concern I have is how low the mufflers will hang if they are located under the seats somewhere. Will something that is between 3.5 and 4 inches thick hang too low? Will they scrape on speed bumps? Will it look retarded? Etc. What have you guys found?

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Black 1989 RS Convertible w/43,000 mi.
Excellent Condition
LO3 305 w/TBI
12 PSI Fuel Pressure
6* Timing Advance
Open Element 14x3 K&N
Hypertech Thermomaster
160 Degree Thermostat
Low Temp Fan Switch
Eddlebrock RPM Muffler
No Cat/No AIR Injection
B&M Stage 2 Shift Kit
17"x8.5" ATP 5 Spoke Alloys
P 245/45 Goodyear Eagle
HP Ultra Plus Tires
Lakewood Control Arms

Coming Soon:
3.73 Gears
Headmann Headers & Y Pipe
Lakewood Pan Hard Rod
MSD Wires and Coil

ONEFINE8T9

it will scrape and look rigged up. My father tried having that done to his old 82 trans am a long time ago and it never worked out right. He went to various muffler shops to have it done and paid alot of money. Everytime he went over n e kind of bumb they would slam the floor board or hit the ground. He also had headers to but they came down to far and to make such a sharp bend would acctually hurt hp.

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1989 pontiac firebird
bright red extior(just repainted)
grey interior
5 spd
305 TBI (stock)
WS.6 formula wheels
3.73 posi rear end
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system: 2 10" MTX thunder 2000 in a Professionally done custom bandpass box.
Blaupunkt CD player
Blaupunkt 4x6 and 6x9
600 watt rockford fosgate 4.6 amp

future mods Borla exahaust maybe???

FRMULA

Don't be a victim of the school of thought that says you need true duals to make power, check out Mufflex. They make an excellent collector pipe system for 3rd and 4th gens. They also have a off road y-pipe that is designed to work with Hooker Super Comp Headers. I bought this system this summer when I did my engine swap and am VERY HAPPY with it.
http://www.mufflex-performance.com/
Good Luck.



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'88 Formula

gsmann

I just got true duals and would trade nothing for it....it sounds awesome and the performance really kicked a--. Don't just look at studies, i mean they're trying to sell their mufflers too. i know from experience i have 2.5" pipes going into 2 40 series flowmaster that are under the passenger seat.....

never scraped yet. my muffler guy tucked everything higher than the stock pipe. really awesome job..

i would recommend it if you want to be different...

rich1034

If you really want to be different, do what my best friend did, he ran MAC headers and y-pipe, but cut the Y out out ran dual 21/2 pipes all the way out down the factory location and mounted 2 one chamber flowmaster race mufflers in the factory muffler location, sounds great, and you can't even see any of the exhaust