exhaust question

[WVUFELLA]

hey guys i have a 440 bored .30 over with high compression trw pistons... a 484/506 cam.. a torker 440 intake with 1 7/8 tti headers and i am somewhat near the exhaust stage and i wanted to put 3" on it but several people have told me that with no more than i have done to the engine that 3" could actually hurt the car if there is not enough back pressure.they said to go with 2.5 pipes. I did some checkin and the 2.5 are cheaper and the local guy can do those where the 3 inch pipes i will have to order cuz the local guy cant bend 3 inch. I am new to the game so i have no choice but to leave this question totally to yall. what should i do???any comments would be appreciated  thank you in advance

[Chryco Psycho]

it is not htat easy , it depends what the engine is being used for , for high power & higher rpm use with ported or aftermarket heads 3" for sure , with highway gears & mostly used in the under 4000 rpm range 2.5 " could give better power & milage

[WVUFELLA]

so would it be safe to say if the car is not gonna be a track car ... mostly used to drive to and from car shows and an occasional rip and tear that i would be able to use 2.5? I would like to take ti to the track one or two times just to see what it would do but for the most part it will not be used to race . ya think 2.5?

[Chryco Psycho]

2.5 should be fine

[moper]

I doubt whther you'd notice anything other than a noise difference. The 2.5 does just fine on most stuff, unless you're searching for that last bit of power. 3" sounds cool tho...lol. much louder...

[HP2]

There was an article in one of the mopar rags about a year ago with the same type of exhaust question. They used a completed Super Bee with a reasonably mild 440 and a 2.5 exhaust on it for the baseline. The swapped it out for the 3" system and power and torque went up, but not a huge amount. I think it was maybe 10 no more than 15 horsepower. Will you notice that much difference, probably not.

BTW, there is no such thing as just enough or good back pressure. Any back pressure can cause reversion which can contaminate the incoming charge.

[A383Cuda]

The bigger pipes tune for higher HP numbers whereas the smaller pipes tune for higher torque numbers. Someone going to the drag strip would prefer the larger exhaust whereas your weekend driver benefits from the 2.5's.

[Chryco Psycho]

There is no good backpressure as stated above , what happens with smaller pipes is increased velocity / scavenging , this is generally a good thing until it become restrictive