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Old 04-07-2020, 11:43 AM
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Default Jegs or Summit 2 1/2 Exhaust Kit for 70-81 T/A

Has anyone ever used the Jegs or Summit brand exhaust kit on their Trans Am? If so, how did you like how it fit? I don't want to run into any interference around the rear sway bar.

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Old 04-07-2020, 12:16 PM
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I used this kit on my 74 formula. I had to buy head pipes as I used stock manifolds. It fit well and didn't interfere with any of the (stock) suspension. It does take some time to tweak it up into the body. I also used the band clamp type connectors.
Nice sound to it but not overly obnoxious!

https://www.jegs.com/i/Dynomax/289/89021/10002/-1

Good read on a Camaro forum about the exhaust kit.

http://nastyz28.com/threads/the-big-...-today.111795/
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Old 04-08-2020, 11:41 AM
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I'll second the Dynomax 89021 kit for the F-bodies. Fits good and I like the mellow sound the ST cross flow Dynomax muffler provides. Hard to beat the price for a specific design kit.
And if you want more noise Dynomax makes an ultraflow style crossflow muffler that fits this system too.

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Old 04-08-2020, 01:32 PM
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Did this kit use the stock mount locations? I installed the flowmaster kits years ago on my 73 Formula and it required drilling holes in a couple places.

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Old 04-08-2020, 02:02 PM
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Yes, the cross flow muffler of the Dynomax kit uses the original in and out pipe configurationa so factory hangers work.

Flowmaster transverse never used the original in and out pipe configurations (inlet was actually at the top of the muffler, very unusual) so those original type hangers you see on the 70 and up F-bodies would not work.

It's one of the reasons I favor the Dynomax kit.

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Old 04-08-2020, 02:11 PM
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It doesn't look like the Dynomax system is overly expensive. Cost is one thing that looked good on the Jegs or Summit Racing kit with turbo mufflers. I may look into the Dynomax kit if the fit is good. Thanks for the help everyone.

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Old 04-08-2020, 02:37 PM
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For what it is, the price is hard to beat. It's aluminized piping, like Flowmaster, but half the cost. Has an "H" pipe which a lot of people here seem to prefer. Pipes are all 2 1/2" and mandrel bent.
Been a while since I bought one but if I remember right, the muffler isn't stainless but it can be replaced with the 17553 ultraflow welded X crossflow which is stainless. More free flowing but also a little louder.

As cheap as this system is to buy, you can buy the extra ultraflow muffler to try, and you're still in it cheaper than a flowmaster kit.

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Old 06-15-2020, 10:03 AM
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I just wanted to give a little feedback on this. I started to buy the Dynomax kit but it was not in stock and it would have been a couple months out was my understanding. I wanted to have my exhaust finished sooner than that so I bought the Summit Racing 2 1/2" exhaust kit and it fit very well. I used Pypes brand downpipes and flanges and was easily able to adapt the ram air manifolds to the Summit exhaust kit. The pipes seem to tuck up underneath the car fine and they seem to go over the axle just fine. The tailpipes bend out of the way of the rear sway bar and there is plenty of room by the rear brake line. I haven't installed splitters just yet but I can't imagine that it would be very hard to do if you wanted splitters. I haven't ran my car yet to see how the Summit turbo mufflers sound. It costed roughly $375 for everything including the Pypes downpipes/flanges and it took me maybe 2-3 hours to install everything and weld everything up to the muffler.

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Old 06-15-2020, 10:09 AM
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Sorry to hear on the Dynomax deal. That kit comes and goes. They run it in batches and when Jegs gets them in stock they don't last very long. They seem to be a very popular kit. They are one of my favorites for an F-body.

Good to hear the Summit kit fits nice. Usually these kits aren't much of a problem for someone like yourself if you have some patients, skill, a welder and a little time.

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Old 06-17-2020, 07:49 AM
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I used a Flowmaster American Thunder kit in the 90s, on my '71, it fit well. I have a 9" rear, the tubes are larger than the 10/12-bolts, so with many kits, 2 1/2 is about as big as you can go, and no way will a crossflow muffler fit. The tubes can hit inside the U-bends.

One thing I didn't like about it is it has H pipes, and due to funding at the time, I just went with the mufflers provided. At the time, no 2 1/2 tips were available, so I held up an original to the tailpipe, cut it with the same length and angle, and chromed the entire tailpipes. Turned out nice.

Going to be replacing this setup once I turn my attention to the bird project, nice to see some input on these systems.

.

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Old 06-17-2020, 08:35 AM
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Regarding the over the axle tubes, that's the only issue I have with those Flowmaster transverse kits.
They have the inlet pipes entering the top of the transverse muffler, rather than the typical side entrance. This creates an axle tube clearance problem even on a stock rearend, making it necessary to mount the muffler as high as possible, and sometimes that's not enough. It also keeps you from being able to tilt the muffler as needed for tank and rear end clearance.

If you use the Pypes transverse system, or the Dynomax transverse system, they still use the OEM style side entrance for the over the axle pipes, and as such they can be bent to follow the contour of the rearend floor tunnel much more closely giving more clearance.

I've used them with aftermarket Strange 12 bolts, 33 spline axles with larger than stock axle tubes and they work with ample room.

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Old 06-19-2020, 02:21 PM
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Don't know if this will help you, but here I go. The following pixs are of the mocked up exhaust system on my 1973 TA before the drive shaft is put in. The system is an American Thunder system without Flow Master mufflers. and is mandrel bent 2.5 inch system. The Flow Master mufflers were replaced with Texas T/A mufflers.
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Old 06-19-2020, 02:22 PM
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more pixs.
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Old 06-19-2020, 02:28 PM
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Hm, my tailpipes are diff, I will have to get some pics and post...

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Old 06-19-2020, 02:33 PM
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Quote:
Originally Posted by HWYSTR455 View Post
Hm, my tailpipes are diff, I will have to get some pics and post...

.
HWYSTR455,

The system was recently purchased and the tailpipes tips are chromed and welded in already from Flow Master

Hope this helps.

Jim

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Old 06-19-2020, 02:35 PM
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Interesting. Yeah, when I said I chromed the tailpipes, I mean all the way from the muffler back. But that kit looks like an improvement.


.

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1970 GTO Judge Tribute Pro-Tour Project 535 IA2
http://forums.maxperformanceinc.com/...d.php?t=760624
1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car
https://forums.maxperformanceinc.com...ght=procharger
Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be
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Old 07-08-2020, 11:10 AM
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Just installed the Dynomax 89021 kit and the 17553 ultra flow muffler as Formulajones had suggested on my wife’s 1973 TransAm. Fit good very little trimming was required. Connected them to Tri-y headders. Plenty of ground clearance
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Old 07-08-2020, 11:15 AM
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Few more pics
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Old 07-08-2020, 11:19 AM
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Quote:
Originally Posted by lovedemnewfies View Post
Just installed the Dynomax 89021 kit and the 17553 ultra flow muffler as Formulajones had suggested on my wife’s 1973 TransAm. Fit good very little trimming was required. Connected them to Tri-y headders. Plenty of ground clearance


You'll like that system. Not overly obnoxious, nice sound, and no drone that I've experienced. Very good system for very little money.

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