2-1/4 or 2-1/2 inch exhaust system?

[Chatt69chgr]

I am planning a std 440 build---a little peppier than stock but that's it.  Plan on using stock cast iron exhaust manifolds.  I understand that the standard H-pipe is 2-1/2 inch and that the std hemi mufflers neck down to 2-1/4.  The tail pipes are thus 2-1/4 as are the exhaust tips.  Is this setup OK for my build.  Or should I plan on keeping the exhaust 2-1/2 all the way out?

[mikesbbody]

i guess it depends if you want to keep it stock or not. If it were me id go 2.5 all the way.

[Ghoste]

I'd go 2.5 as well.

[charger2fast4u]

im getting ready to buy my exhaust for my stock for now 440 im getting 1 7/8'' headers and 3'' full exhaust with x pipe from TTI  exhaust id suggest 3''but if you don't want to go that big i would get 2.5''

[firefighter3931]

Chatt...2.5in all the way to the bumper would be preferable. Stay away from a chambered muffler as they are restrictive and will hurt performance. 



Ron

[440fan]

What do you guys think of Dynomax Ultra Flows or Magnapacks? I currently have an original all stock original paint 69 440 R/T 4 speed and it has a NOS exhaust and muffler installed. Thinking of just replacing the muffler to get better flow. Of course the originals will go in my basement. What do you think? Will they give me a little better performance or not? Thanks.

[firefighter3931]

What do you guys think of Dynomax Ultra Flows or Magnapacks?

By Magnapacks do you mean Magnaflow ?

Both the ultraflow and magnaflow are true strait thru design mufflers and will help with power. The sound is a deep rumble that is pleasant to the ear unlike a chambered "flowmaster" which has an obnoxious tinny sound. Mufflers that are restrictive create backpressure and hurt performance....so depending on how restrictive your current mufflers are there could be quite a difference.

There are several members here who have gone to the ultraflows and noticed significant improvement in power output. I have yet to hear one comment saying that the change was one they regretted making. 


Ron

[440fan]

I mean Magnaflow magnpacks. The current mufflers are NOS 69 mufflers and I am assuming they are restrictive. I do not want to change out the pipes because they are like new and are I think 2 1/2 inch pipes. Just thinking of getting more sound out of the rear and maybe even more power. Even though it already hauls a**. I kind of baby the car but new mufflers really are inexpensive to put on. Thanks.

[Blown68Coronet]

Hey Ron
Are you saying the Coronet is obnoxious to you??
I'm stepping up to the Ultra flow 3 1/2 rounds for next yr so there.

[471_Magnum]

Performance-wise, necking down one size at the tailpipes is harmless. By the time exhaust gases are that far down stream, they have cooled and condensed substantially. The smaller pipe downstream will support the same mass-flow-rate as the larger pipe up stream.

Going with 2.5 will just make it louder.

I have to bite my tongue whenever people claim their after market cat-back exhaust systems are big power adders. Ricers are by far the worst offenderd hanging coffee can fart pipes off the taill end of a stock exhaust.

[chargerman68]

got a 2 1/2 from jegs.looks and sounds great and cheap

[firefighter3931]

Hey Ron
Are you saying the Coronet is obnoxious to you??
I'm stepping up to the Ultra flow 3 1/2 rounds for next yr so there.

Actually, on your car the Flowbastards don't sound tinny (just LOUD  )....maybe it's that 750hp blown 440 in front of them ! 

Good call on the Ultraflows....don't forget the x-pipe 



Ron

[Goodz]

just did my exhaust in 2.5 inch.  sounds nice, although its only a 318, so i dont know how it compares to your cars.  cherry bombs go on in the next couple of weeks, so i think that will sound even better.

best of luck on your build.