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73-87 Chevy _ GMC Trucks
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3" ?
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Topic: 3" ? (Read 8142 times)
The dream
Registered Users
Posts: 147
3" ?
«
on:
September 22, 2011, 10:00:45 PM »
When is a 3" exhaust necessary? what can i expect?
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Never give up.
HAULIN IT
Senior Member
Posts: 1542
Re: 3" ?
«
Reply #1 on:
September 22, 2011, 10:09:15 PM »
Are you talking a single 3" or duals? As to when it's really necessary depends on what your referring to. As in, what are you using the truck for? How are you measuring gain/loss, ect. A 2 1/2" pipe flows allot of gases, the bad bends or restrictive mufflers are really the problem if there is one. Not sure what you are referring to as far as "What can I expect?" Lorne
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The dream
Registered Users
Posts: 147
Re: 3" ?
«
Reply #2 on:
September 22, 2011, 10:38:47 PM »
I'm talking about duals with a probable "h" setup, 78' K20 with a 383, longtube headers and super 44's, street performer with very light offroad. No towing intended.
Just wanted to know what size i should use, 2 1/2 or 3"?
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slammed79
Senior Member
Posts: 1367
Thou shalt not drive stock
Re: 3" ?
«
Reply #3 on:
September 22, 2011, 10:55:06 PM »
I'd go 2.5" personally. A 383 doesn't need 3", and it'll just make it really really lound with the 44's.
I had a 2.5" system on my 79 with a 350/350 and Flowmaster super 44's, sounded plenty tuff and flowed really well.
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74 C10 Long bed 350/SM465 Lowered on 20's
Praise the lowered
The dream
Registered Users
Posts: 147
Re: 3" ?
«
Reply #4 on:
September 22, 2011, 11:05:50 PM »
So aside from being loud at 3", performance wise I can expect good things/enough size at 2 1/2" ?
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slammed79
Senior Member
Posts: 1367
Thou shalt not drive stock
Re: 3" ?
«
Reply #5 on:
September 22, 2011, 11:33:33 PM »
Yeah. Performance wise you'll be just fine with that 383. Plus you'll get the cost savings over 3". I had a muffler shop quote me almost $100 more for 3" over 2.5"
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74 C10 Long bed 350/SM465 Lowered on 20's
Praise the lowered
The dream
Registered Users
Posts: 147
Re: 3" ?
«
Reply #6 on:
September 22, 2011, 11:55:25 PM »
I hear you, 150 dolar diference between 2 1/2" and 3".
Besides i am a little worried about the noise, just that i didnt want to sacrifice performance.
Thanks a lot guys.
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beastie_3
Senior Member
Posts: 3170
Josh
Re: 3" ?
«
Reply #7 on:
September 23, 2011, 12:55:46 AM »
no benefit to go 3"
Your motor isnt big enough
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79 K10
Semper Fi
73-87 Chevy Trucks Facebook Page
firefighter
Frequent Member
Posts: 462
Re: 3" ?
«
Reply #8 on:
September 23, 2011, 07:10:19 AM »
I'd go with the 2 1/2" also.
I was running 3" on my 1200 HP pro street ChevyII and it was a pain to install and hide.
Plus the downside is, if you go too big, it'll hurt your low end (talking motor). A little back pressure seems to make the low end a little snappy and crisper.
This is just my opinion of course.
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Irish_Alley
Tim
Global Moderator
Senior Member
Posts: 13319
Family is not an important thing. It's everything.
Re: 3" ?
«
Reply #9 on:
September 23, 2011, 11:56:24 AM »
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If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley
When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes
VileZambonie
Global Moderator
Senior Member
Posts: 19022
Re: 3" ?
«
Reply #10 on:
September 23, 2011, 05:24:37 PM »
Built Big Block likes 3"
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, ___
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74 GMC
,
75 K5
,
84 GMC
,
85 K20
,
86 k20
,
79 K10
screamin86
Junior Member
Posts: 661
Re: 3" ?
«
Reply #11 on:
September 23, 2011, 09:47:04 PM »
If I remember correctly isn't dual 2 1/2 good to like 500-550 hp anyway?
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86 k10 lwb 4x4:350 .040 214/224 444/466 112lsa performer rpm 1406 lt's summit racing th350 2800stall
03 yukon xl:tint debadge full boltons
86 ta:lm7 hot cam boltons
The dream
Registered Users
Posts: 147
Re: 3" ?
«
Reply #12 on:
September 24, 2011, 10:32:58 AM »
Well thats good to hear, i don't really know how much HP I'm packing in the 383, but i don't think I'm in does numbers (maybe i can do another post with my set up and somebody can give me an idea? is that possible?). Actually its been a learning nightmare. thats what you get when you don't have any experience. Ive drop a little over 3000 in the engine and i still need some accessories. So know I'm really tight on cash, and saving 150-170 dollars sounds good to me. I JUST NEED TO RIDE AGAIN !!!
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Never give up.
screamin86
Junior Member
Posts: 661
Re: 3" ?
«
Reply #13 on:
September 26, 2011, 06:18:56 PM »
Some more info on the motor would be helpful.
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86 k10 lwb 4x4:350 .040 214/224 444/466 112lsa performer rpm 1406 lt's summit racing th350 2800stall
03 yukon xl:tint debadge full boltons
86 ta:lm7 hot cam boltons
The dream
Registered Users
Posts: 147
Re: 3" ?
«
Reply #14 on:
September 26, 2011, 09:44:26 PM »
I wont hold anyone to their answer, so a good guess will be appreciated.
350 block bored .060
400 crank with 3.75 rods/ 5.7 rod length
Flat top pistons
World SR torquer iron heads, 67cc, 170cc intake, 2.02 intake, 1.6 exhaust.
Thumpr Hydraulic Flat tapped camshaft, Op range 2000-5800, 227 241 @ .050, 479 465 @ 1.5:1, 107 lobe
Edelbrock RPM Performer Intake 1500-6500
Comp Cams Rocker arms 1.52 Rollertip
MSD Ignition Kit, 43TS ACDelco's
600 cfm Edelbrock Carb
B&M 2000 stall on a 400 auto (haven't figured out the gear ratio but it haves 14 bolt FF)
So what kind of torque/HP am i looking at?
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3" ?