hello. has anyone had any experience with the flowmaster 3" first gen dual exhaust header back kit? all my local muffler shops tell me its impossible to run 3" tailpipes between the leaf & quarter panel. also my 68 is lowered 1-1/2" which i think makes the space to run big tailpipes even more limited. please throw some suggestions my way. thanks,bill.

Well I can tell you your Muffler shop is full of Sh?t , I have a full Stainless setup on My vert they fit with about !/4 of an inch on each side .
Mark .

hey mark. bitchin exhaust system!!! can you tell me about it? thanks.

Just find an exhaust shop with a guy that owns a good car.
I am just blown away by how many shops I checked out that told me I needed to stay with a 2 1/4" system - because I need the back pressure.
Your typical exhaust shop doesn't know performance.

Most of these Shops have back pressure in there Heads , it's just easier for them to fit the 2 1/4 so they just tell you that .You need to dig deeper . Bill drop Me a private Email and I give you My number if you want . That system on My convert took Me about a week off and on to do , it just needs to be polished and it's ready to rip .
Mark .

Mark, did you do that exhaust yourself? It looks great. I did mine recently, but not as nicely as yours. One thing I did was to use quick disconnect conical couplers at rear of mufflers, similar to what you did (you used flat ones). I can have entire exhaust system out in about 10 minutes.

I am using Flowmaster 2.5" tail pipes out the rear and I'll tell ya, it's tight between the body and leaf, maybe 3/8" on each side. I gotta think a 3" tail pipe would need a little dimpling in the pipe in those areas, but that should be real easy.

I'm still trying to find system that will eliminate interior resonance. I have tried Flowmasters 40 and 50 series Deltaflows, plus I now have Magnaflows. All produce interior resonance at about 1800 to 2200 rpm's. It's driving me crazy........

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because I need the back pressure.

thats my favorite!
need it:
like a hole in my head,
or a 2-barrel carb:D

The backpressure myth will never be dispelled. But it doesn't matter for those of us who know better.
It's about pressure wave tuning, plain and simple.

Nice work on the 3" SS system by the way!

I'm in the process of building a full 3.5" "X" system for my Nova. It won't be stainless though. I'll even have 3.5" tailpipes exiting between the spring and rear quarter. Novas have much more room there than a Camaro.

3.5" might be overkill, but I enjoy the work, and I just gots to know if it will be an improvement over the 3.0" setup I removed!

Ron

Very nice , rear end, link, shocks , pipes, but going to 3" was one reason I stayed with the 2.5". The rear tail pipes are the worst fit, but if you have done all of this, maybe you could do so new bends to get that pipe in there...How about and oval tube to squeez thru that area?

....How about and oval tube to squeez thru that area?

Yeah, this is what I meant by "dimples". But I would just make it oval in the area where it is close to the leaf/body.

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I was referring to something a little smoother, like an elongated section or retangle with nice round corner, sorta squashed?

Dr Gas can supply oval sections that mate to round sections.
Check em out!
Ron

Yes My system was all built here on the claim , grinding and welding on Cars is still alot better than listening to My 5 and 7 year old trying to kill each other , boy I can't wait until this car is done . My springs are in the stock location I moved the shocks inboard so they missed my rear disc setup . But My convert is bone stock in the rear and the three inch fits very well . I had all the stainless flanges cut out by My brother inlaw on there Lazer table at work . With the resonance problem I found with the X pipe it doesn't seem to be a problem .
Mark .

If fit does become a problem on the tail pipes just remember that from a performance standpoint, the size of the exhaust piping after the mufflers is not as important as the size of the pipe leading to the mufflers. Now you cant' go crazy like having a 550hp engine and running 3 inch to the mufflers and then 1 3/4 tail pipes, but 3 inch tot he mufflers and 2.5 inch tail pipes will not produce a noticeable difference in power, but may reduce sound levels little. The reason they don't reduce power is due to the cooling and slowing of the exhaust gasses thru the mufflers, once this occurs, the gasses don't need as much volume in the pipe to easily pass.

........With the resonance problem I found with the X pipe it doesn't seem to be a problem .
Mark .

How can you say this about the resonance? It appears you haven't driven the car on the road yet. I have 3" X-pipe on my car and the interior resonance is VERY noticeable and annoying, in 1800 to 2200 rpm range only.

After you get car running, please post a comment about your level of interior resonance. I'm curious to see how much you experience with that great-looking exhaust.

thanks

Chevy-SS no My car has not been run , but My others have , First one Blown 509 in a chevy pichup three inch all the way no problem , second one 67 Beaumont 2dr post aluminum headed 468 full solid roller holley comander 950 MPFI Tremec TKO600 full three inch out the back , no problem . If half these guys would get rid of there flowmasters and used a good muffler you may fix the problem . I built a complete system for My fathers truck using no X pipe with Borla's He just loves it .
Mark .

I agree to the above,, Installed set of 40's on my 69 with 2.5 pipes after headers all the way,, Couldnt hear during or after I shut car off due to resonance,,, Same way on my 57. On the camaro I went to flomaster transverse kit 17104 and then put two simple flow thru 12" glass packs on .. Shazzam,,, I could hear my phone ring. And car was deadmated and jute padded all the way.... Those 40's , 50's are killers.

I agree to the above,, Installed set of 40's on my 69 with 2.5 pipes after headers all the way,, Couldnt hear during or after I shut car off due to resonance,,, Same way on my 57. On the camaro I went to flomaster transverse kit 17104 and then put two simple flow thru 12" glass packs on .. Shazzam,,, I could hear my phone ring. And car was deadmated and jute padded all the way.... Those 40's , 50's are killers.

Did you use glasspacks AND Flowmasters together? Or are you saying you replaced the Flows with the glasspacks??

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The 40s are loud? I have them on my 67 and they are too quiet for me. I'm gonna take them off and put single chamber flows on it when the new motor goes in. I also had their 80 series cross flow muffler on my 99 SS and it was horrible. I have since, switched to full length headers, 2 1/2" with x pipe, and single chambers flows. The car sounds incredible now and its my inspiration for getting the same setup for my 67. Here is a video of my 99 SS. http://www.ls1sounds.com/true_duals/TDs-Flowmaster-1chamber_JetHotLT_2.5inFlowtechX_99SS-A4.MPG I gradually layed into it brought it up to about 4500 in first, let it shift into second, then took it to about 5500.

I started out thinking Flowmasters where so great , after doing My third system using them and being sick after a two hour drive , I switched over to Stainless borla's , they are a bit more Money but what a big differance .
Mark .

i agree with you all on the flowmasters being too loud. when i bought this car it had 2-1/2" dual chambers on it dumped @ the axle & it was so loud it was embarasing to drive. then i had some tailpipes installed from there to the rear bumper & it was still way too loud. all that was with a mild 300hp small block. so now i estimate my new 434sbc should pump out about 550hp+ which makes me think (along with alot of suggestion here & elsewhere) that i need a 3" system. i like the idea of 3" pipes before the mufflers & 2-1/2" after. has anyone run their exhaust tailpipes where they dump before the rear tires out the side? if so what were the results? loud? any inconveniences? in your guys years of experience running all sorts of different combos, what are the best flowing & quietest mufflers on the market? thanks for answering all my dumb questions, bill.

Bill don't dump them in front of the tires , go over the axle and out the back . Please try a set of Borla's and they polish up great . I have a buddy that runs the Hooker mufflers and they are ok also , I just like to stay with stainless .
Mark .

SS, Yes, 40's or 50's seem to produce too much resonance and noise out back . Replace entire system with a Flomaster 17104 K Kit that had the transverse muffler with it,, Thats the 80 series muffler. Resonance gone but still a little noisy. Put the 12" flowthru glass packs and now sounds close to what car did when new. Nice deep rasp tone.

.......Put the 12" flowthru glass packs and now sounds close to what car did when new. Nice deep rasp tone.

Where did you locate the 12" glasspacks?

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......has anyone run their exhaust tailpipes where they dump before the rear tires out the side? if so what were the results? loud? any inconveniences? in your guys years of experience running all sorts of different combos, what are the best flowing & quietest mufflers on the market? thanks for answering all my dumb questions, bill.

Your questions ain't dumb, and the answer ain't easy, at least not in my case.

My car is a '68 with 454 (alum heads, roller cam) and Hooker Super Comp 2" headers, engine is around 525hp.

Interior resonance is my biggest gripe, and I have been trying all kinds of systems in the last few years. First was Flowmaster's American Thunder 2.5" H-pipe system with 40 series Deltas and tailpipes just behind rear wheels. Wicked loud inside and out, just way too loud overall. Then added Flowmaster full tailpipes exiting out rear. Better but still too loud. Then went to 50 series Deltaflow mufflers, real nice sound outside car but still the resonance. Then went to 3" X-pipe, retaining the 2.5" 50 series mufflers and full tails. Awesome sound outside, but interior resonace still there. Then went to Magnaflow straight-through mufflers; still interior resonance.

I'm kinda going crazy with this resonance thing. I've had lengthy talks with tech reps from Flowmaster, Magnaflow and Corsa. They all pretty much agree that the resonance issue is a very tricky one to solve. Some guys have it, some don't. Resonance depends on a huge and widely disparate variety of factors including; engine, headers, exhaust size, exhaust pipe shape, mufflers, cam, intake manifold, sound damping on body and more.

Hopefully you get luckier than me, but I'm still fighting the resonance battle.

SS as stated above with using a bottle type muffler , why don't you try some resonators just in front of the Mufflers , or something that will spin the exhaust have a look at the Jeg's catalog they have something in there .
Mark .

I recently spoke with a shop here in sac. & the guy brought up a point that i had never thought about. he said that the design of flowmasters are echo chambers. so putting them under your car makes your car an echo chamber as well in a sense. souds logical to me. i have narrrowed down my choices to spintechs or borlas. can you guys help me narrow it down from here? pros/cons? i love the hollow sound of flow's which makes me want to try the spintechs, but i don't want to have to do this exhaust system twice because its too loud. thanks so much! bill.

I like the sound of the Borla's compared to the Flow's , they are quite at cruise but sound like a Nextel cup car at wide open throttle . And the borla's look better .
Mark .

SS as stated above with using a bottle type muffler , why don't you try some resonators just in front of the Mufflers , or something that will spin the exhaust have a look at the Jeg's catalog they have something in there .
Mark .

This was a good idea, thanks. I looked in Jeg's and ordered some Car Chemistry collector inserts (pic below) after speaking with their tech guy. I bought the 3-disk set which will slip into the collector.

http://www.carchemistry.com/images/ccinssm.jpg

I can reduce the number of disks, if needed, to tune away the resonance. The CC tech guy said these really help with resonance.

I'll post results after I get them installed.

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Please let us know if it works .
Mark .

Hey guys, just to add my 2 cents, I am running the stainless works 3" system with crossover. Mine runs all the way back with no problem. I love the system and I must say that they went up fairly painlessly and look outstanding.