yea I have a 95lx 4.6L. The muffler system goes exaust manifold to primary cat on each down pipe after the first set of cats there should be an O2 sensor to measure levels after the first cats then it drops 2 into one and into the third cat and after that there is another O2 sensor to measure emissions again to make final adjustments to meet certain standards back at the ignition and fuel curves then the resonator then the mufflers. I though you had an fox bodied t-bird like devon. An answer to your question is that you have to reinstall all three O2 sensors into the new system or else you computer will throw the check engine light on and have codes for the O2 sensors. a true dual is relatively easy to do it is ususally very expensive and not worth the money a 4.6L has very poor torque and freeing up too much backpressure will hurt the low end torque. our cars need it to. I personally lost 1-2 tenths in the 60ft times but gained 2 tenths at the end of the quarter and 1 mph. a cat back system is the best choice in my opinion. The dual exaust wont help you as much as compared to a 5.0 because the fox bodied t-birds have alot of bends in the exaust as opposed to our cars where it is a relative straight run to the rear. I would invest in an after cat system or just some new mufflers but steer clear of the flowmasters go with dynomax "quiet ones" the ones that only growl when you mash the pedal. My flowmasters suck I blew out a baffle after 6 months and it is louder than hell in the cabin while running at 65mph they suck. I am going to install a muffler where the resonator is after the third cat and then throw some crome tips on the y pipe in the back.<br><br>Later<br>Black_Thunder

yup, 4.6l... Ok, a twist.. what about going with a catback system, and not dual, but replacing the primary cats, with high flow Hedman Hedders cats for example? Also, I heard the 3rd 2-1 resonator/cat is a big restrictor, useless and should go. I'm just trying to get the most power possible without altering the engine itself... too complicated. by the way, when you say "I personally lost 1-2 tenths in the 60ft times but gained 2 tenths at the end of the quarter and 1 mph" is this when you tried duals? <br><br>thanks hnicksta

cat's tricky item depending on where you live. In nj for example all cats have to remain intact but can be replaced by aftermaket ones as long as it passes the sniffer test for emissions. You are going in the wrong direction for hp and performance the restriction in the 4.6L is the heads and intake side not the exaust side. that is why I reccomend just getting a cat back system. the factory units flow well enough to support up to 250-260 hp without any problems but if you want the sound go for the cat back system it will only give you about 3-5 hp not enough to make a difference really. <br><br> my loss/gain was with only dual flowmasters in the stock locations.(loss in backpresure changed my torque curve higher into the rpm range and the increased hp gave me the 1 mph. I can only imagine the loss/gain with a true dual exaust the 4.6L needs the backpressure. I would invest in a cat back exaust from dynomax or bypass the exaust completely right now and get some underdrive pulleys or a set of gears like 3:55's or 3:73's depending on how much highway driving you do. the 3:55's for a lot of highway driving and 3:73's for local around town driving.(steeper gears worse gas milage on highways) This will give you the plant you in the seat feeling you are looking for. and get a locker (posi) unit too if you can afford it. a complete drop in unit from ford motorsport is like $600 the gears will run you about $160 and about $200 installation. your/my birdy's weren't made to fly they were made to soar with comfort and style not tearing up the asphalt. hp and low e.t.'s are expensive and so if you want the sound and looks just get the exaust.<br><br>LAter<br>BLack_thunder<br>Founder NETCOA find it under makes/ford/thunderbird/netcoa<br>or <a href=http://www.geocities.com/black_thunder1995 target=new>http://www.geocities.com/black_thunder1995</a>

&gt;&gt;steer clear of the flowmasters go with dynomax "quiet ones".&lt;&lt;<br> <br>I agree,I think they are called Ultra Flow.<br>You want performance or sound?

best performance possible but want to be low key... but will sacrifice low key if necessary. I like being inconspicous... thanks hnicksta

Black thunder, thanks for all your info... really appreciate it, will most likely loose 3rd cat and go with a magnaflow resonator and a catback... these gears you are talking about, I would have to get speedometer gear to match, count the teeth etc. and get the chip reburned as well and other stuff? I currently have 3:08 Was wondering what type of performance gain this will give and how much top speed will be lost with either set of gears, a couple of tenths in the quarter mile? 600 buck include posi? I'm realizing now making this car fast, high HP and low ET will $$$, so just trying to do a few things here and there... so its somewhat faster... thanks hnicksta

tranny gear yes, chip no. depending on mods anywhere from 2 tenths to 5 depending on gear ratio. no mph gain, only et gain long story don't have time now to explain it. prices vary state to state so you will have to find out price. <br><br>Later<br>black_thunder