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Discussion Starter · #1 ·

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I hear 50/50 opinions on Summit (and Jegs) exhaust systems. Some say OK, some have a frustrating time with fit. I can tell you from experience that their turbo mufflers (18") are too loud, at least for me. I switched to 20" Dynomax Super Turbo #17749 and love them. Night and day difference as far as sound quality and drone control. As far as headers I have no experience with Summit's, but I'm done with long tube headers on street driven cars. I recently put these on my 350 Chevelle- https://classicmusclecarexhaust.com/p/thornton-sbc-headers. I used them with Pypes Big Block downtubes and Pypes SGA30 straight duals. Along with the Dynomax mufflers the system sounds awesome. The headers fit great and mimic the outlet location of an Small Block exhaust manifold so you use a factory style Big Block head-pipe because the outlet is 2.5" instead of 2". For me, this is the way to go.
https://classicmusclecarexhaust.com/p/pypes-64-72-gm-a-body-el-camino-true-dual-2-5-sga30
https://classicmusclecarexhaust.com/p/pypes-chevrolet-downpipes-64-77-big-block-log-manifold
https://classicmusclecarexhaust.com/p/2-5-dynomax-super-turbo-mufflers
 

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1964 Chevrolet Chevelle Malibu 4 door
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I tried the Summit 3" aluminized steel exhaust for my 64 and man, do NOT try. Spend a little more and get the flowmaster setup. My pipes hang down in full view and I could not even get the over axle / tailpipes to come close to fitting. As stated above the summit mufflers are really loud. I started with the full welded turbo mufflers, do not recommend, then went with their regular turbo mufflers, still loud. It does sound like a muscle car, but I'm sure my neighbors hate me. Any WOT runs and your ears ring afterwards. That's my stupid trophy for going 3" and being cheap with mufflers.

Ended up spending $150 more and getting flowmaster tailpipes, they fit a lot better. You can see how Summit just got the stock pipe routing and put 3" pipe in the bender. It hits the trunk floor, upper arms, diff cover if you're running an aftermarket stud girdle, springs, AND hangs under the gas tank.
The 2.5" may be a little more forgiving? No amount of trimming would bring it in to work. Flowmaster tailpipe on left, you can see the height difference is dramatic.



You can see how the pipes from headers back hang below the frame, this is with the summit turbo mufflers.


This is the fully welded turbo mufflers, they're extremely "clappy", you can hear the exhaust echoing off of houses, this was about 3/8 throttle.


The fully welded sounded awesome with turndowns though, but again, hearing loss is guaranteed.
 

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Hotwire, I think we touched on this subject before- you're absolutely correct in everything you've said. Flowmaster, Pypes, and MagnaFlow have put an awful lot of R&D time into designing their systems, and it shows. Summit mufflers are inexpensive, so I tried an 18" set on my Chevelle. WAY too loud and getting louder by the mile. Put on Dynomax Super Turbos #17749 and I'll never go back. That old saying "There's never enough money to do it right the first time, but there's always enough money to do it over again" was so true in this case. From a fitment standpoint, you can't go wrong with a system from either of those 3 manufactures mentioned above.

https://classicmusclecarexhaust.com/
 

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Discussion Starter · #5 ·
I hear 50/50 opinions on Summit (and Jegs) exhaust systems. Some say OK, some have a frustrating time with fit. I can tell you from experience that their turbo mufflers (18") are too loud, at least for me. I switched to 20" Dynomax Super Turbo #17749 and love them. Night and day difference as far as sound quality and drone control. As far as headers I have no experience with Summit's, but I'm done with long tube headers on street driven cars. I recently put these on my 350 Chevelle- https://classicmusclecarexhaust.com/p/thornton-sbc-headers. I used them with Pypes Big Block downtubes and Pypes SGA30 straight duals. Along with the Dynomax mufflers the system sounds awesome. The headers fit great and mimic the outlet location of an Small Block exhaust manifold so you use a factory style Big Block head-pipe because the outlet is 2.5" instead of 2". For me, this is the way to go.
https://classicmusclecarexhaust.com/p/pypes-64-72-gm-a-body-el-camino-true-dual-2-5-sga30
https://classicmusclecarexhaust.com/p/pypes-chevrolet-downpipes-64-77-big-block-log-manifold
https://classicmusclecarexhaust.com/p/2-5-dynomax-super-turbo-mufflers
Those headers are cool, thanks for sharing that. If they are indeed the same size and shape as stock manifolds, that would make installation much easier.
 

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Discussion Starter · #6 ·
I hear 50/50 opinions on Summit (and Jegs) exhaust systems. Some say OK, some have a frustrating time with fit. I can tell you from experience that their turbo mufflers (18") are too loud, at least for me. I switched to 20" Dynomax Super Turbo #17749 and love them. Night and day difference as far as sound quality and drone control. As far as headers I have no experience with Summit's, but I'm done with long tube headers on street driven cars. I recently put these on my 350 Chevelle- https://classicmusclecarexhaust.com/p/thornton-sbc-headers. I used them with Pypes Big Block downtubes and Pypes SGA30 straight duals. Along with the Dynomax mufflers the system sounds awesome. The headers fit great and mimic the outlet location of an Small Block exhaust manifold so you use a factory style Big Block head-pipe because the outlet is 2.5" instead of 2". For me, this is the way to go.
https://classicmusclecarexhaust.com/p/pypes-64-72-gm-a-body-el-camino-true-dual-2-5-sga30
https://classicmusclecarexhaust.com/p/pypes-chevrolet-downpipes-64-77-big-block-log-manifold
https://classicmusclecarexhaust.com/p/2-5-dynomax-super-turbo-mufflers

Those headers are cool, thanks for sharing that. If they are indeed the same size and shape as stock manifolds, that would make installation much easier.
 

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Discussion Starter · #7 ·
I tried the Summit 3" aluminized steel exhaust for my 64 and man, do NOT try. Spend a little more and get the flowmaster setup. My pipes hang down in full view and I could not even get the over axle / tailpipes to come close to fitting. As stated above the summit mufflers are really loud. I started with the full welded turbo mufflers, do not recommend, then went with their regular turbo mufflers, still loud. It does sound like a muscle car, but I'm sure my neighbors hate me. Any WOT runs and your ears ring afterwards. That's my stupid trophy for going 3" and being cheap with mufflers.

Ended up spending $150 more and getting flowmaster tailpipes, they fit a lot better. You can see how Summit just got the stock pipe routing and put 3" pipe in the bender. It hits the trunk floor, upper arms, diff cover if you're running an aftermarket stud girdle, springs, AND hangs under the gas tank.
The 2.5" may be a little more forgiving? No amount of trimming would bring it in to work. Flowmaster tailpipe on left, you can see the height difference is dramatic.
I bought the 2.5" system for my Buick and it fit well. The turbo mufflers were not loud at all. I mean, the car shook the house, being a big block and all, but it didn't have that piercing sound and was quiet enough at speed to have a conversation in a normal voice.

That was 10 years ago, so perhaps they have changed the design.
 

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Andy- Those headers were a breeze to install. My Chevelle is a '70 with P/S & A/C- no issues. The factory bottom A/C bracket obviously doesn't fit and I left it off for now, but the other 2 brackets are still holding the compressor rock steady. I also used a spacer between the header and the downtube on the drivers side like there is on the Pass. side just to give a little more crossmember clearance. Using these headers with Big Block 2.5" factory headpipes or Downtubes from either Flowmaster or Pypes gives you a complete 2.5" system for your Small Block without the hassles of long tube headers. I couldn't be happier with the final result. At the risk of repeating myself, here is what I installed on my Chevelle:

https://classicmusclecarexhaust.com/p/thornton-sbc-headers
https://classicmusclecarexhaust.com/p/pypes-chevrolet-downpipes-64-77-big-block-log-manifold
https://classicmusclecarexhaust.com/p/pypes-64-72-gm-a-body-el-camino-true-dual-2-5-sga30
https://classicmusclecarexhaust.com/p/2-5-dynomax-super-turbo-mufflers
https://classicmusclecarexhaust.com/p/chevelle-exhaust-tips-69-72-super-sport-2-5
 

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Discussion Starter · #10 ·
So what did you decide on for your exhaust? I too am interested in those stainless steel Summit headers.
I'm just about to order. I think the stainless one is the same as the basic aluminized steel version. I put the 2.5" on my Buick years ago and had zero complaints.

Also going to oder the Classic Air system, so the CC is going to get a workout today :)
 

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Got a Summit 2.5" header-back system for my '71 Nova. It was terrible. The drivers side fit nice but the passenger side, it musta been for a Ford truck. I still kick myself for that one.
 

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Discussion Starter · #12 ·
So what did you decide on for your exhaust? I too am interested in those stainless steel Summit headers.
I ordered those Thornton headers and the basic Summit aluminized exhaust. The one I put on the Buick was still new looking after 7 years so I figured the $200 I saved could be used elsewhere.
 
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