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08-30-2010, 12:26 PM
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#1 |
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Registered User
Join Date: Apr 2008
Location: east, tx
Posts: 149
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headers tested.
I just had my headers dynoed with a lower hp and lower rpm motor than mine.
Same cubic in engine though. They lost 30+ hp and 40+ torque. Just wondering what I should see at the track with some new headers. That should be a seat of the pants difference right?
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68 chevy truck ls3, 418ci, pump gas 10.81@121.8 all motor. 1.47 60ft 70 suburban 350 tbi swap, 700r4, work in progress |
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08-30-2010, 12:44 PM
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#2 |
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Registered User
Join Date: Nov 2007
Location: Bay Area, Ca
Posts: 2,841
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Re: headers tested.
What were the two sets of headers?
I'm thinking about doing something different on my truck for headers too since the 418 will be going in real soon (maybe next Sunday). I thought about getting a set of 2" big block headers and modifying them slightly to go over the frame rail and exit where the wheel well used to be.
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------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49 |
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08-30-2010, 02:17 PM
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#3 |
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Registered User
Join Date: Apr 2008
Location: east, tx
Posts: 149
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Re: headers tested.
The set I have now is doug thorley tri y's. They are 1 5/8 into a 2" then 3" collector.
I am having some made that are 1 7/8 stepped to 2" long tube headers.
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68 chevy truck ls3, 418ci, pump gas 10.81@121.8 all motor. 1.47 60ft 70 suburban 350 tbi swap, 700r4, work in progress |
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08-30-2010, 03:06 PM
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#4 |
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Registered User
Join Date: Nov 2007
Location: Bay Area, Ca
Posts: 2,841
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Re: headers tested.
I was thinking about doing something similar to a 1 7/8 stepped to 2" I might even go a touch bigger given the amount af N20 I plan on putting through it.
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------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49 |
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08-31-2010, 12:45 PM
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#5 | |
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On a budget like Fred Sanford
Join Date: Oct 2005
Location: Topeka, KS
Posts: 2,031
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Re: headers tested.
Quote:
1FAST68: I'm not surprised a 1 5/8" primary choked down that 418ci, IMO a 1.875 primary is as small as I'd go on a n/a motor like yours.
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'85 Silverado swb: 383 stroker, 10.5:1, vortec heads, 232/238 roller cam, RPM air gap, performer 750 carb, stainless longtubes, 3" duals/super 44's, T56/4.11 383ci build / exterior refresh thread '98 Camaro z28: 370ci twin turbo 370ci build '01 Tahoe LT 4x4: 5.3, longtubes/ory, magnaflow duals, custom tune....wife's DD |
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08-31-2010, 10:00 PM
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#6 |
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Registered User
Join Date: May 2002
Location: NJ
Posts: 910
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Re: headers tested.
I bet the curved looked a lot different though. Peak numbers aren't everything. How did the area under the curve look?
1-5/8 primaries are too small for a 418.
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83 C10 Stepside (SOLD, it was a blast!) 383 MASS-FLO EFI/TKO II 600/3.90 Posi 10 bolt S475 and C4 DM running, fine tuning turbo=  Douchebag Racing: Runs Fine all the Time |
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09-01-2010, 12:23 PM
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#7 | |
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Registered User
Join Date: Nov 2007
Location: Bay Area, Ca
Posts: 2,841
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Re: headers tested.
Quote:
It is when your TQ converter flashes to your peak TQ 
__________________
------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49 |
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09-01-2010, 04:30 PM
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#8 | |
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Registered User
Join Date: Apr 2008
Location: east, tx
Posts: 149
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Re: headers tested.
Quote:
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68 chevy truck ls3, 418ci, pump gas 10.81@121.8 all motor. 1.47 60ft 70 suburban 350 tbi swap, 700r4, work in progress |
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