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Old 07-01-2014, 04:27 PM
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Exhaust help

I have a 1979 Camaro with a 383, K1103 summit cam, 882 performance heads, 4 speed manual, long tube headers true duals( 2.25) with super 44s and turndowns. The exhaust is way to small. I was thinking 2 1/2 but want the 3" for the loudness and a 2 years down the road I want to turbo it. I was looking at the summit 3" true duals with turbo mufflers. I'm looking for under $360 because I also need new headers. What do you all think?

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Old 07-01-2014, 05:19 PM
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With the cam and heads you are running the larger exhaust may over scavenge and you will lose low end power,with your 383 you should save up and invest in some better heads before you think exhaust mods.This would give you more flow and not break the bank:White Performance Detail Description The compression increase should help with the "loud" you are looking for too.
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Old 07-01-2014, 05:27 PM
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the heads are port and polished with new valve springs and seats (did them myself for free). The block has been decked and the heads have been cut down. Has a .015" gasket. Flat top pistons, forged rods and a 400 crank. compression test and people on here say about 10.1:1.
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Old 07-01-2014, 06:03 PM
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Quote:
Originally Posted by 79CamaroMatt View Post
the heads are port and polished with new valve springs and seats (did them myself for free). The block has been decked and the heads have been cut down. Has a .015" gasket. Flat top pistons, forged rods and a 400 crank. compression test and people on here say about 10.1:1.
Yeah that's nice and I appreciate your hard work as do many others here. But no matter what you do to a set of 882's compared to equal work on a set of L31 Vortecs you're short 40-50 horsepower with the 882s. This gets even better with modern aftermarket heads.

Much has been learned about combustion chamber shapes and subtle differences in port shape as it mostly affects wet flow as well as mass flow that come together starting with the L31 head and the GMPP aluminum Fast Burn which is a conventional cooling LT4 head. The differences are subtle and easy to miss visually, but bolting a set of these things on is quite an eye opening event when you step on the go pedal.

Obviously the small chamber L31 or Fastburn and other 64 cc chambers are going to raise the compression much too high for a 383 with flat top pistons. But the aftermarket doth provide with the same chamber and port configurations but with 76 cc chambers. I highly recommend starting a head replacement fund at your bank, you’ll be glad you did.

Bogie
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Old 07-02-2014, 03:00 AM
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As has been said, your heads are hurting your combo and limiting the cam choice to under 1/2" lift. Exhaust pipe diameter won't change much except the cool factor and noise.

Example:

-Go up to 3" exhaust with better headers - +20 HP...maybe.

-New heads and better cam that takes advantage of the higher lift and springs you get with it - +60HP probably more.

If you want a turbo your going to have to change the exhaust anyway, why not do it then?

Your poor heads will limit your turbo boost, you will need to address this issue at some point anyway unless you plan on limiting to under 6 PSI.

Cash is obviously tight, save it for something you really need.
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Old 07-02-2014, 09:04 AM
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I put Summit's 2.5" true dual system with their turbo mufflers on my '71 Camaro with a healthy 427. I loved it, and it sounded great. Not crazy loud at idle, but really barked when you got into the throttle. I think a 2.5" would be plenty for your setup, and still work with some engine upgrades.
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Old 07-02-2014, 01:42 PM
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yeah I know 882s but my friend did some research and 882s came in two castings. The ones I have are performance heads according to him. They are good enough till I rebuild the engine years down the road. I'm not spending $1200 on heads when I can LS swap for the same price. The exhaust I have now is old 2 1/4" now and is way to small for a 383. The cars an every day driver with some beating on for time to time.
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Old 07-02-2014, 02:29 PM
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Yes, there were 882's put on Corvette and Camaro Z28 applications, with 2.02" intake valves and screw-in studs, and may get called "performance heads" because of this, but as far as being real performance heads in a power making sense...they ARE NOT. Neither of the 882 versions have any better ports than any other "smogger" mid 1970's head, ... you have what most performance guys call a polished set of turds.

I would hesitate to even call a 240 HP mid-70's Corvette engine a performance engine, considering the same 882 headed short block with 1.94" Valves and a standard cam was used in the same year trucks.

A $600 set of Aluminum Assault heads will get you an easy 60-70 hp boost, even with the 2-1/4" current dual exhaust...which is about the right size for your current power combo.

2-1/2" mandrel bent pipe is good to 600 hp, I never found a difference between that and open 3" header extensions on a low 11 second street/strip car.

3" would be overkill, and will be awful loud unless you spend big $$$ for Borla or MagnaFlow mufflers and add resonator tips.

You are really deluded on the 882 heads, sorry to say.
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Old 07-03-2014, 12:05 PM
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if 2 years down the road your going to turbo it, run 2.5'' into a single 3''
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Old 07-03-2014, 04:42 PM
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The thing is the collectors are 20 years old and I think they are 2 1/4 collectors into straight pipe had super turbo mufflers now has 44s so its already loud. I'm looking for piss off the neighbor loud. my friend has a 72 Camaro with a 3" exhaust and it sounds good. My high performance teacher told me it the exhaust is the same size as the collector its pretty much like open headers. I really don't care about losing 10ftlbs of torque because its an old 383 in a 1979 Camaro Berlinetta
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Old 07-03-2014, 06:43 PM
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If ya want piss off the neighbor loud then just run open headers. Works every time!!
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Old 07-03-2014, 06:55 PM
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Quote:
Originally Posted by squarebob View Post
If ya want piss off the neighbor loud then just run open headers. Works every time!!
Yep, or worse! I fired my 464c.i. BBC up with fenderwell headers uncapped in the driveway, and cracked the neighbor's side window. They were OK about it, and I quickly replaced it.
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