Exhaust pipe size with a 440

[Charger Fan]

Looking to replace exhaust system on '73 Charger SE. The stock 440 exhaust system has 2 1/4 inch OD exhaust piping. I originally thought it was supposed to be 2 1/2 inch. I want the system to scavenge properly and don't think 2 1/2 inch would hurt. Does anyone have any experience with this?

 

[69L48Z27]

I think 2.5” would be fine. Any engine or header modifications?

 

[AR67GTX]

Some OEM Mopar systems were also 2-1/2” to the mufflers and 2-1/4” tailpipes.

 

[Cranky]

Some OEM Mopar systems were also 2-1/2” to the mufflers and 2-1/4” tailpipes.

Duals? What OEM cars came with 2 1/2" pipe? Only had one OEM 440 powered car and iirc, it had 2" or 2 1/4" dual exhaust on it. Wouldn't think that an early emissions lower compression engine would have anything bigger than a 2 1/4 on it.....

 

[zyzzyx]

The Mopar Engines manual recommends 2-1/2". Engine masters did a whole episode on exhaust
system sizes on the dyno and found that 3" was optimal, but 2-1/2" was right there. So many choices!

 

[33 IMP]

I like the way mine runs..... with 3 1/2 to the bumper.
Edit: to be honest, it's probably too big. I built it in anticipation of the 520 I'm building. I didn't want to change the header flange ( homemade four bolt) and reducers aren't available for my flange, so I just used the same size tubing as the collector.

 

[WileERobby]

2 1/2 straight through, from header to tip. All you need.

 

[gtx6970]

I have a 383 that has 2.5" TTI and it runs real good.
I also have a 440 car thats 2.25" manifold to tail pipe and it runs just as well.
Both car are fairly close to stock internally

IMO a 2.25" system on a stock B / RB engine car will be just fine untill it gets lots of mods or starts living in high rpm range all the time

 

[Runcharger]

2 1/2, 2 1/4 tailpipes as a minimum. It isn't a 360.

 

[33 IMP]

Duals? What OEM cars came with 2 1/2" pipe? Only had one OEM 440 powered car and iirc, it had 2" or 2 1/4" dual exhaust on it. Wouldn't think that an early emissions lower compression engine would have anything bigger than a 2 1/4 on it.....

68/69 440 b-bodies had 2 1/2 h-pipe head pipes, and 2 1/4 tailpipes.

 

[moparedtn]

For the OP's specific application, the stock piping:
- 2 1/2" headpipes
- 2 1/4" from the mufflers back
CBS71440ET-1971-74 B-Body 440 Engine Complete Exhaust for Ex

(As others have already stated, this is true of a lot of factory 440 cars in prior years as well).

 

[AR67GTX]

Also hemi cars.

 

[Charger Fan]

Anybody ever purchased exhaust parts from this place;Muscle, Classic Car Exhaust Tips
Their price on the slotted bazooka style tips seem to good to be true?

 

[Big Bad Dad]

I never understood why Ma Mopar put the 2-1/2" pipes back to the mufflers, and then choked down to 2-1/4" tailpipes. Wonder if it was engineered that way for a reason, or just to make it easier to get the smaller tailpipes in between the springs and gas tank on the production line?

 

[33 IMP]

I never understood why Ma Mopar put the 2-1/2" pipes back to the mufflers, and then choked down to 2-1/4" tailpipes. Wonder if it was engineered that way for a reason, or just to make it easier to get the smaller tailpipes in between the springs and gas tank on the production line?

The exhaust cools significantly at the muffler,so less volume of gasses. So it doesn't need to be as large, and also for clearance reasons. (And smaller pipe is cheaper!).

 

[Rick Moore]

My experience has been the big blocks have 2-1/2 exhaust pipes and a 2-1/4 tailpipe. I've had a 383 69 Charger, 70 Superbee 440 six pack and a 71 GTX with a 440. That was the exhaust on all of them.