Allright, I wasn't even sure to begin what to search for, but I tried anyways and got no hits.

I'd like to run a true dual exhaust, but not just how everyone does 'em on these cars. I've had a loud car for years, and personally i'm tired of it. It's unpleasent to ride in after a while, and attracts way to much attention.

My plan was for 2.5" true duals with shorty headers (I already have the shorty's, i'd like to keep them for ground clearence), 2 cats, an h-pipe, 2 mufflers, and then 45* turndowns before the axle. And obviously the piping to get everything back to the rear end. I'm hoping the cats along with the mufflers will quiet it down somewhat. I know the car moves along decently, I don't need to advertise it to everyone, including the local police.

Here's what I was looking at for cats: http://store.summitracing.com/partde...part=WLK-15038

I'm pretty much decided on those, their cheap, have heat shields (my floor gets REALLY hot right now), and should do the job quite nicely. The area I really need help with is the mufflers. I'd like to stay with a round or "bullet" style muffler. Once again, ground clearence is a big factor here. I've looked at a few, but I can't really tell what i'm looking for. Obviously I don't want this to be a choked off exhaust, but I'm not gonna be running the Borla XR-1 race mufflers or something. So hopefully you guys could make some suggestions?

Finally, like I mentioned earlier, i'd like to maintain my shorty headers. I haven't asked any local shops yet, but do you think they'll have a problem bending the 2 pipes 45* or so as opposed to normal LT headers where it just runs straight back?

-Thanks for your help in advance, Brandon

 

no reason to do true duals with shorties, just get a quality mandrel bent y-pipe along with high flow cat and a nice 3" mandrel catback. If you need extra flow get a cutout installed for when you need the extra flow.

 

Because a quality mandrel bent y-pipe is a decent chunk of change....

I don't want a cut-out realy, plus I don't like the look of the tips at the rear of these cars, hence keeping them hidden with turndowns.

And lets say I were to go with LT Headers, anyone have any experiance with these: http://store.summitracing.com/partde...5&autoview=sku

Their cheap, and come with all the hardware/gaskets, but does anyone have any experiance with how ground clearence is, how they perform, etc.

 

i am curious too..i am in the same boat as you....i am nearing the 400 hp mark and need more exhaust than single 3" and was thinkin of using those LT's and i have to have cats

 

i have the headman longtubes but there not the way to go if u want cheap/quiet. if u run true duals its going to be loud...unless u put a really restrictive muffler to quiet it but then u will hurt performance.

the headers are cheap but then u'll have to either make the entire exhaust yourself or have someone do it for u which will cost sum $.

the total price for my 3" true duals with xpipe is...

headman LT=120$ when i got em 2 yrs ago
headman 3" Sbend extensions=30$
summit universal 3" xpipe kit=100$
force 3" muffers (2)=70$

total: 320$

but i did all the work, and did heavy modifiacation to the undercarage not to mention ground clearance problems that ur gona run into. but mine is loud and i love to wave at the police as i pass them

 

I'm planning something similar to that, although I already have the Hooker 2460 shorties. My idea is true duals with an H back to a single Magnaflow crossflow in the stock position. I know it's expensive (believe me, I know!), but exhaust sound is important to me and I'm sure no matter what I do my car will be fast when I put a 383 in there.

The concern with your plan is where you will fit a muffler. From the sound of it, you will end up with a short length dual exhaust, turn downs underneath the car, and small bullet mufflers. That will be loud. There's just no space underneath the car for a decent sized muffler except after the rear axle.

 

I'm prepared to spend the money, and I honestly think I can get it all done with a totally tally under $600 with the price of new Hedman LT's. I've toyed with the idea of the Mufflex exahust also.

 

thewolf...your 383s gona need a good flowing exhaust...skimp on the exhaust and u will really decrease the performance of the 383. look at how a 305 picks up .5s in the 1/4 from an exhaust upgrade and thats not even a highpo motor by anymeans. even the 350tpi gains alot. now do that to a 383 which needs more exhaust just because of the increase in displacemnt but also the increase in air moving/powerband yadda yadda. dont skimp. your 383 will need a 2.5" mandrel bent system that flows good minimum.

wats the price of the new headman LT's? 140$?

u could get it done without paying sumone to instal but ur gona have a hardtime making it quiet... theres no room for traditional mufflers. i got mine to sorta work but they hang low. im gona cut into the floor and tuck them up when i rip the motor out

 

customblackbird - the pipe specs are as follows: 2.5" dual mandrel bent stainless steel with an H-pipe, all the way back to a dual in, dual out crossflow Magnaflow muffler (also stainless). I know I'll catch some flak for having shorties, but at least they are 1-5/8 and a 3" collector. I have an entire box of mandrel bends from www.mandrelbendingsolutions.com ready to go when my TIG welder gets his garage open.

86 350 - $600 sounds cheap. Again, the shorter the exhaust route, the louder the note. Your cats and an H-pipe will help out some.

 

I don't think it sounds unreasonable. You figure the headers run $150, 2 cats is $120, 2 bullet mufflers is about $80, h-pipe is like $30, and then just a few feet of 2.5" pipe. I figure it comes to about $450 and then I think $150 is a fair price for a shop to weld it up (i'm doing the headers if I go with LT's) and supply some hangers. I realize shorter will be louder, i'm making it about as long as possible, the dumps will be right before the axle.

Also, does anyone have any experiance with a variety of bullet mufflers? From what I hear the Moroso Spiral Flow's are pretty loud, but the Dynomax Ultra Flo's seem to be some of the "quieter" bullet mufflers and should still flow good.

 

thats a good exhaust. and should be fine for your 383. are u sure u wanna go with the Hpipe? yes they are easier to install on our cars but the xpipe will make more power/flow better. still an Hpipe will be a good addition.
the cross flow muffler if im not mistaken is a pretty big muffler... where are u gona put that thing?

86 350... i had true duals before my current setup with dual cats and afterburner mufflers and the cats didnt really quiet it that much. i got a noticable decrease in exhaust noise when i intalled an xpipe even tho i upgraded to louder force mufflers.

an xpipe/hpipe will decrease exhaust decibles. addition of cats might help slightly but a system that is longer with quieter mufflers in the stock setup will help as well. the quieter the muffler the more restrictive it will become to a certain degree.

 

I went with an H-pipe for the smoother, more classic muscle car sound. The crossflow is a big muffler, 11"x5"x24" if I remember right. It is about two or three inches longer than the stock one, but will still fit fine in the normal location (sitting sideways behind the rear axle). I think I will angle cut the tips just below the fender for a low profile installation. Hopefully it will be a sleeper.
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86 350 - I think the Moroso spiral flows are race-only. As in, they just knock the decibel level down from open headers at road race tracks. Magnaflow makes stainless bullet mufflers for something reasonable, maybe $50 or $60 each. Check out their 4" round body mufflers.

My muffler shop charged $40 for a muffler install with a couple of hangers and tips. $150 might be low, depends on your area and the shop.

 

yea it should fit i figured thats where u would have to put it.
ur gona be running them both over the rear axle? i hope u dont cut the pipe with the scissor action of the rear... BMR sells a modified peice that will allow enough room to run dual pipes over the rear axle in the stock location.

i think the slashed tips would look good. i usually dont like when the tips poke out the back of our cars... looks sumwat tacky for my taste. hiding them would make it more of a sleeper and more like they shoulda came from the factory.

 

Hoestly, i'm not that concerned over the 3-4 hp to gain from an x-pipe over an h-pipe. Will an x-pipe be quieter then an h-pipe however? Cause then I could probably justify the extra $$$.

 

Well I don't know if the x-pipe will quiet it down more than an H-pipe, but it will sound smoother, less throaty if you know what I mean.

 

Yeah, BMR has that panhard rod and support relocator. Their website says it supports up to 3" dual exhaust over the axle. Do you think my 2.5" will make it? It's been too long since I've been under there to look and see.

 

i would get the part... its reinforced as well as nice looking lol... no really i would get it just to be sure...wouldnt hurt. i think u'll be pushing it with dual 2.5s even tho im sure someone has done it before.

86 350... i read an articel in an old carcraft/chp and they did a test with a mild 350 it had a 3" true dual system on the dyno. they got a base number and then tested just the addition of an Hpipe i believe it made a good but more power but then just the addition of an xpipe the engine came alive with maybe 10hp peak over the hpipe but wat u dont see is that it increased the powerband and made equal to more tq/hp throughout the rpm range. the xpipe i believe made something like 35hp/tq in the mid rpm ranges over a non hpipe/xpipe setup.

i believe the xpipe would be quiter than the hpipe, since its way more efficient, and equalizes the exhaust pluses more effectivly not to mention has a larger area where the opposite sides of the exhasut are connected and open to eachother. i got a good bit reduction in exhaust loudness with the installation of the xpipe... everyone could tell. xpipe kits are only 100$ if u get a 3", less if its a 2.5" or 2".
hpipes are old technology, even tho effective they are not as effective as xpipe.
i lost alil down low but 2400rpms and above u can hear and feel the xpipe kick in, the exhaust note changes, it become smoother and then its like a rocket, i def picked up sum power in the mid range and upper rpms.

i vote xpipe, its throaty up until 2400 then it smoothes out nicely

 

I have the spiralflows and they are very loud, especially when you get on it. Does have that classic sound with my cam though.