Mac vs. Flowmaster ?

MY 85 GT

10 Year Member
Mar 7, 2008
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New Jersey
Ok i just had the exhaust done all mac, long tubes...off road h-pipe and mac cat back...Im not to impressed with the sound to me its not that loud....If i change out to 2 chamber flows how much louder will it sound? And how much work do you think it will e to switch mufflers...also what is the part number for the 2 chamber flows? Thanks
 
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The quite exhaust is due to the long tubes. I have had two car with long tubes and both got quieter with them.

I like MAC better than Flows because you don't have to mess with clamps that never come off later, or welding, which has to be cut apart later. The MAC has all ball and sockets.
 
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The quite exhaust is due to the long tubes. I have had two car with long tubes and both got quieter with them.

I like MAC better than Flows because you don't have to mess with clamps that never come off later, or welding, which has to be cut apart later. The MAC has all ball and sockets.

So you would leave the Mac's on is that why its quieter then i would like it....would it be louder with flows tho?
 
So you would leave the Mac's on is that why its quieter then i would like it....would it be louder with flows tho?

I would leave the MAC's on. They are loud as hell on my notch. I have a MAC catback on my 91 notch 5.0L and my 81 notch which I put a 2001 4.6L engine into. They both have stock shory headers/manifolds.

See...when I pulled the motor outta the 2001 GT donor car...it had longtubes on it and I hated the exhaust note. When I installed the motor in my notch, I used the same exhaust except I ditched the l/t's for stock manifolds and the car was 10 times louder and better sounding.

IMO Flows and MAC, sound very similar.
 
I just switched from Flowmaster to MAC and the MAC"s made the car louder and IMO soounded better too. MAC is the loudest system you can buy according to the sticky in the 94-95 section.

Yes, longtubes make the car quieter. Shorties for sound longtubes for hp and tq.
 
Yeah i like the sound of MAC's i do i think its because i have no cats it makes it sound like a 60's truck...lol I pit long tubes on because i plan on a H/C/I and running a 150 shot also...after i do the rear...new gears 3.73's new posi...new axles....so on and so on....lol so i'll leave Mac's on...Also in fornt of the driver muffler it has a small leak which im bringing back today to get fixed....
 
I love the sound dont get me wrong...idle is awesome when you got on it awesome... crusin its quiet like on the highway you barely hear it.....I do have a small exhaust leak by the muffler i need to get that fixed then it should sound better maybe what im hearing is an exhaust leak making it sound not so good....lol
 
I always thought that MAC's were pretty loud.:shrug:

Do you still have those '85 heads on there? It should get louder or change tone if you swap to a better flowing head.

This is from an old 5.0 mag.
soundingoff.jpg
 
I always thought that MAC's were pretty loud.:shrug:

Do you still have those '85 heads on there? It should get louder or change tone if you swap to a better flowing head.

This is from an old 5.0 mag.
soundingoff.jpg


Yes my motor is all stock for the moment....:) I have an edelbrock 650 avs carb...and the timing is bumped and accel igniton and wires....I am going to be installing a set of AFR's 165 i think im going with a TFS stage 1 cam and a performer rpm air gap intake by edelbrock....oh yeah also going to install 1.7 rockers...Also a 100-150 shot of nitrous....The rear is next tho....i have 2.73's im going to go with 3.73's corba posi unit...FRPP gears...all new bearings...Moser 31 spline axles im going with UPR upper & lower a-arms...sub frames...i want to do the suspension 1st so when i add power i can hook i did exhaust for now because i couldnt take the stock exhaust anymore..it was Quiet.....So i hope the tone will pick up once i do the motor work....
 
That graph is with other parts stock,as far as stock h and everything then macs are not that loud at all.but with no cats they sound amazing and even better with and x pipe matted up to them.i know when i put my cats back on my car was pretty quiet.
 
That graph is with other parts stock,as far as stock h and everything then macs are not that loud at all.but with no cats they sound amazing and even better with and x pipe matted up to them.i know when i put my cats back on my car was pretty quiet.


I dont have cats..I have an off road H pipe...the car is loud when getting on it but driving normal you barely hear it...On the highway nothing...Idle is great...taking off from a light awesome...but if im crusin around town in 3rd you dont even hear it....
 
The loudness of an exhaust depends more on the engine than anything. If you've got a stock engine then don't expect it to sound like a racecar no matter what you put on it. Look for the thread on my buddy's 347 exhaust clips...his exhaust got 10x louder compared to the stock engine. You can barely hear yourself think driving his car and it has full exhaust.
 
The car in the graph was a 6750 rpm screamer:D, and it was done in an enclosed area so it is going to be on the loud side. But the test was controlled, same car, same room, same conditions; and like I said earlier the stock '85 heads aren't exactly the highest flowing head out there.