Author Topic: Headers & Exhaust  (Read 2703 times)

Offline smokin77

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Headers & Exhaust
« on: January 30, 2003, 07:26:00 PM »
I just ordered Dynomax headers, and dual exhaust. Im also getting rid of the AIR system. Does anyone know what i can expect for an increase in power? Oh, and my truck is a 85K10, 350sbc.


Offline bored and stroked

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.
« Reply #1 on: January 31, 2003, 03:37:00 PM »
Id say somewhere between 15-45hp. You didnt say what size any of the tubing is, so thats the low range [1.5 headers with 2" exaust] to the high range [1 3/4" headers with 3" exaust]

If you got the correct sizes [1 5/8" primary with 2.5" collectors and 2.5" exaust] then you should have about 25-30hp and torque.


Offline oscarone

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duel exhaust
« Reply #2 on: January 31, 2003, 11:32:00 PM »
Be sure when you change to duel exhaust you have a "balance" pipe between the two sides.  It improves torque.  If not, your two cyl.  banks are operating at different pressures.  If what you ordered does not come with a balance pipe take it to a "GOOD" exhaust shop.  It won't cost much to have one put in and a good shop will know where to put it.  Speed shops/muscle car shops will know what to do.


Offline Eric 85K10

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Re: duel exhaust
« Reply #3 on: February 07, 2003, 12:43:00 AM »
I've got a stock 305 in my 85 K10. It has dual exhaust without cats and no H pipe. Would that make the exhaust pop when I let off the gas after accerelating?

Also could I just slap some headers on my 305? I put headers on my 327 in my 65 pu, but it doesn't have any vaccum hoses and crap. I'm planning on replacing the 305 soon, but I like the sound of headers and It couldn't hurt to have them ready for my new small block ;)  


Offline 83CHEVY

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Re: duel exhaust
« Reply #4 on: February 07, 2003, 10:05:00 AM »
No Mr. Eric 85K10, that would not cause the pop in your exhaust when you decelerate using the engine.  You just hear it better now :) .  If you want that pop to go away, replace the diverter valve in your A.I.R. air injection system.  Trust me on this one, I spent a lot of money trying to figure out what was causing this same thing on my '83.  I even replaced the timing chain and gears!!!  Save some money and get the valve.

Mike

Edited by: 83CHEVY  at: 2/7/03 11:09:28 am

Offline smokin77

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Re: dual exhaust
« Reply #5 on: February 09, 2003, 07:01:00 PM »
I just put headers and dual exhaust on my 85k10. I just ripped the smog crap off. My used to pop after you let off the gas, because it was leaking. Its fine now, sounds real good, and it only set me back $300. And about vacuum lines, just take a screw and plug em up! My truck runs great!
Tony


Offline Eric 85K10

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Re: dual exhaust
« Reply #6 on: February 10, 2003, 12:05:00 AM »
diverter valve, where exaclty is that and how much is a new one?


Offline smokin77

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Re: dual exhaust
« Reply #7 on: February 10, 2003, 05:27:00 AM »
Im not sure how much, go to www. competitor.com, but i think its near the alternator on the passanger side of the truck. I will look it up, if im wrong ill correct the post.
Tony  


Offline Sierra4x4

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Re: dual exhaust
« Reply #8 on: February 15, 2003, 07:13:00 PM »
Im really interested in knowing about the dynomax headers. Im considering them greatly for my 350. if you would either post a reply or even email me @ solaceofwinter@yahoo.com about the install and your gains id appreciate it. Except im going to try and add an intake manifold & throttle body spacer as well.


Offline smokin77

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Re: Header Installation
« Reply #9 on: February 15, 2003, 10:56:00 PM »
Do you have AC, what year is your truck? Mines an 85 with AC and i had two little problems. Removeing the exhaust manifolds is 80% of the work, actually putting the headers on is pretty easy. One problem was on the passenger side there was a big bracket mounted to the frame that had a rubber bumper on it right above the differential, it was in the way of where the header had to go.(and its not going back on). My other problem was the AC bracket suggested by Dynomax didnt fit, but my AC pump seemed to have plenty of support without an extra bracket. I ripped the AIR system off, and pluged the two vacuum lines that went to it. Other than that the headers bolted right up, they clear everything fine, and they dont leak. The only problem is they have been on a week or two and the paint is peeling. If you have any other questions (or if im incorrect about something) just post a reply or email me at: superballs71@hotmail.com
Hope I helped, Tony


Offline Sierra4x4

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Sounds good
« Reply #10 on: February 16, 2003, 09:28:00 AM »
Well my truck is a 79, The a/c 'pump' or whatever it is isnt even on the truck but ill get the a/c bracket because i think i have a donor pump. Anyhow.  I dont have the a.i.r. crap and ive got TONS of room under the hood. (I think you could fit two or three people in there with the hood shut!) What probs did you have getting the old ones off? Any tips? Ive heard you should start the engine a bit first.. What kind of performance did you get? Worth the cash? Ill probably pay a little more and get the coated jobs...


Offline smokin77

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Re: Sounds good
« Reply #11 on: February 17, 2003, 12:27:00 AM »
I would definately get the coated ones. As for performance I was told I would get 10-45 more HP. My engine was still warm when i removed the  manifolds, passenger side came off fine, drivers side I had to work the two center bolts back and forth(tighten-loosen) a little bit.