The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 09-24-2002, 07:33 PM   #1
Chevy Punk
Registered User
 
Join Date: Apr 2002
Location: Blaine WA
Posts: 455
3 inch too big?

Do you think 3" exaust with turbo mufflers coming out in front of the tires will be too big? It is a very mild 350, rv cam and headers. Anyone else have this setup?
Chevy Punk is offline   Reply With Quote
Old 09-24-2002, 07:36 PM   #2
72chevyLWB
Got 20's????
 
72chevyLWB's Avatar
 
Join Date: Oct 2001
Location: Aberdeen SD
Posts: 1,451
You would loose a bit of torque with that exhaust. 2.5" might even be too big. If its a very mild 350, then 2 1/4" would be perfect. If you aren't built up alot you loose torque with bigger pipe.
__________________
99 Silverado Ex-Cab 2wd, Bagged&WhippleCharged
02 Sierra Ex-Cab 4wd 2500 HD
The 72 went down the road.
72chevyLWB is offline   Reply With Quote
Old 09-24-2002, 07:40 PM   #3
Zkast
Account Suspended
 
Zkast's Avatar
 
Join Date: May 2002
Location: Olathe, Kansas
Posts: 929
With a RV (very mild cam) and assuming you have low compression 8.5 or 9.0:1, the 2 1/2 is plenty big if your going dual exhaust. 3" is actually going to cost you some low end torque.

3" would be ok if you ran single exhaust but why? hehe.

I think you'll find most exhaust tuner's will tell you 2 1/4 is where you need to be with that setup. This is based on a stock engine with a rv cam and headers.
Zkast is offline   Reply With Quote
Old 09-24-2002, 07:42 PM   #4
Chevy Punk
Registered User
 
Join Date: Apr 2002
Location: Blaine WA
Posts: 455
Im not as worried about losing a bit of tourqe than i am losing sound. I had 2 1/4 in it before and it sounded really crappy, too quiet.
Chevy Punk is offline   Reply With Quote
Old 09-24-2002, 07:48 PM   #5
Zkast
Account Suspended
 
Zkast's Avatar
 
Join Date: May 2002
Location: Olathe, Kansas
Posts: 929
3 inch with a mild engine will give you a airy sound out of the pipe. Sounds terrible IMHO. Been there an done that already lol. 2 1/2 is the largest I would go and even that is too big for your engine. Get a set of flowmasters on 2 1/4 ( 40 series) and you'll love it.
Zkast is offline   Reply With Quote
Old 09-24-2002, 10:07 PM   #6
slam33
Registered User
 
slam33's Avatar
 
Join Date: Aug 2001
Location: Long Beach, Ca
Posts: 1,432
Thats like using rattle can paint becuse you want the color rather than the finish. Your motor should have 2 1/4 if your going to push more gas thru it then you need to cam it, do the heads to support the cam and intake and carb. Beside that theres nothing worst that a car that sound mean and doesn't have the guts to back it up.
__________________
71 LWB 350/350still working on it but it's going tp be sweet. www.geocities.com/stevemau/slam33page.html

" TARGET=_blank>http://www.geocities.com/stevemau/slam33page.html?1004806705410

</A>
slam33 is offline   Reply With Quote
Old 09-24-2002, 10:51 PM   #7
Crank
Registered User
 
Crank's Avatar
 
Join Date: Aug 2002
Location: Crittenden, KY
Posts: 1,965
Amen Slam33, like these damn little civics with a pipe big enough for me to stick my head in and look around. Hell if you want the sound of a 3" pipe, put a 3" tip on it, but damn that, just build your motor and run as big of pipe that the motor needs; but for now just stick with a little pipe with a halfway decent tip... that way as to not affect your performance much and still give you that airy sound.
Brandon
Crank is offline   Reply With Quote
Old 09-24-2002, 11:20 PM   #8
Ackattack
Senior Member
 
Ackattack's Avatar
 
Join Date: Aug 2002
Location: Valley Center KS
Posts: 3,524
I'm assuming that you're having an exhaust shop do this for you. That being assumed, most do not have mandrel pipe benders. Therefore I'd go with 2 1/2" pipe so that when they bend it it will be about 2.25" at the bends. If you are going with mandrel bent pipe, then 2.25" should be fine.
Ackattack is offline   Reply With Quote
Old 09-24-2002, 11:38 PM   #9
69gmcfleet
Registered User
 
Join Date: Apr 2000
Location: Oneonta, NY, US
Posts: 103
I run the exact setup you described except the 3" pipe.
I have a mild built 350/325hp, headers, straight duals, turbo mufflers, and turn outs before the rear wheels, with 2.25 pipe.
It sounds great. Not too loud though.
__________________
Jeff
'69 GMC K2500 LWB, '74 350/SM465/Rockwell T-221, cnD44/ffD60, 3.73 gears, 31" BFG's
(originally had 305ci V-6)

'05 VW golf
'84 HD Sportster XLX
'68 GMC K2500 parts beast
69gmcfleet is offline   Reply With Quote
Old 09-25-2002, 12:19 AM   #10
dion
72 Cheyenne
 
dion's Avatar
 
Join Date: Oct 2001
Location: San Diego
Posts: 2,086
3 is too big, 2.25 is the norm for that motor, I had that for a while and it was great. I went to a 500 lift cam and switched to a 2.5 pipe with 40 flowmasters. I'm going with delta flow 50's
__________________
Burnout
Idle
1972Cheyenne
1966/67Stouts
dion is offline   Reply With Quote
Old 09-25-2002, 12:37 AM   #11
mikep
Used to have a truck
 
mikep's Avatar
 
Join Date: May 2002
Location: port orchard WA
Posts: 1,552
well lets see . I changed from 3 inch exhaust dumping in front of the rear tires to full length 2 1/4 with dynomax super turbos exhaust exiting after the rear tires. Edelbrock performer cam , headers, etc. Probably close to the same as your build with a little more compression and aftermarket heads. I'll be honest. The 3 inch was NOT too loud although my neighbors might disagree and if anything I think I lost some low end torque with the change to 2 1/4 . I did have the same 3 inch exhaust with a much larger cam before and it was definitely too loud. Its hard to get a feel for 5-10 lbs of torque lost with a big ass truck though and it may just be that now that its REALLY QUIET It seems slower on the bottom end.
__________________
No truck :-(
mikep is offline   Reply With Quote
Old 09-25-2002, 04:14 AM   #12
Pont
I need another Barley Pop
 
Pont's Avatar
 
Join Date: Feb 2001
Location: Grants Pass, OR
Posts: 1,629
Dion, I'm running the Delta 50 series behind my big block. I love them! If you haven't run them before, they are nice and mellow off the throttle but sound good when you get into it. Not as loud as the 40's but I'm not young anymore either. I like them a little quieter than I used to. Keep us posted after installing them.
__________________
67 Short Fleet 4x4

04 Honda CRF450R

89 Toyota 4-Runner

34 Ford 2 door sedan - Long term project


----------------------------------------------
There is a very fine line between "hobby" and "mental illness"
Pont is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 10:59 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com