How Well do Stock Mufflers Flow?? Look here an see.

[Stangtuner]

When the S197 came out Magnaflow tested the Ford muffs to see how they could improve on them.
They decided they could only improve the sound.
In fact the whole system was done very well from Ford.
The Ford Manifolds, and exhaust system was redone for the S197 and they did a very good job.

Add F/I and things change, but for N/A the system is GTG.

Much improved over he 2v setup thats for sure. But gains for 25-35rwhp with the addition of Longtubes is noted as well.

 

[Joach]

The stock mufflers are a straight through design. Not much restriction there.

They are NOT straight through design....

Warlock could be a suggestion if you want best of both worlds....
http://www.jegs.com/p/Flowtech/744884/10002/-1

 

[ixtlan]

Dont think any can type muff is straight thru.
It is a sound bouncing effect.
Want straight thru go Glass Pack.
How Old School would that be?

 

[Joach]

As close as it gets...

Believe CORSA is as close you can get, also taking care of the drone....

 

[Fastmover]

I am still running stocks on my car!

 

[2k05gt]

STOCK:
Muffler weight: 16lbs each
Idle noise: 68 dBA
Cruise noise @ 2000 rpm: 96 dBA
Column Max: 313.8 ft-lb, 289.8 hp
Column Avg: 282.5 ft-lb, 231.7 hp


UN-MUFFLED:
Muffler weight: 0 lbs
Idle noise: 73 dBA
Cruise noise @ 2000 rpm: 99 dBA
Column Max: 311.2 ft-lb, 290.0 hp
Column Avg: 284.9 ft-lb, 227.2 hp


BASSANI R BX-4605-5R:
Muffler weight: 10 lbs each
Idle noise: 71 dBA
Cruise noise @ 2000 rpm: 98 dBA
Column Max: 315.2 ft-lb, 292.8 hp
Column Avg: 287.5 ft-lb, 226.7 hp


Ford Racing GTA M-5230-GTA:
Muffler weight: 14.5 lbs each
Idle noise: 70 dBA
Cruise noise @ 2000 rpm: 97 dBA
Column Max: 315.1 ft-lb, 298.7 hp
Column Avg: 289.2 ft-lb, 226.5 hp


FORD RACING M-5230-5GT:
Muffler weight: 7.5 lbs each
Idle noise: 71 dBA
Cruise noise @ 2000 rpm: 96 dBA
Column Max: 314.9 ft-lb, 292.7 hp
Column Avg: 286.4 ft-lb, 223.5 hp


FLOWMASTER:
Muffler weight: 16 lbs each
Idle noise: 72 dBA
Cruise noise @ 2000 rpm: 97 dBA
Column Max: 314.5 ft-lb, 292.0 hp
Column Avg: 287.8 ft-lb, 225.0 hp


JBA:
Muffler weight: 12 lbs each
Idle noise: 71 dBA
Cruise noise @ 2000 rpm: 98 dBA
Column Max: 313.0 ft-lb, 289.5 hp
Column Avg: 276.7 ft-lb, 218.6 hp