How much are my small headers killing my performance
#2148281
09/05/16 09:16 PM
09/05/16 09:16 PM
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Posts: 501 CEDAR RAPIDS
Plymouth340
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I have a 900 horsepower W7 small block with 1 7/8 headers on it. I put more gear in the rear end. (4.88 to 5.38) and more converter doesn't seem to make much difference on the performance. I'm thinking the headers are holding this thing back big time..runs 9.20s in 3000 da air @ 2800 lbs ???????????
Last edited by Plymouth340; 09/05/16 09:16 PM.
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Re: How much are my small headers killing my performance
[Re: Plymouth340]
#2148297
09/05/16 09:26 PM
09/05/16 09:26 PM
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Joined: Jan 2013
Posts: 174
hustlin hoosier
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We have tried about everything possible with headers and never found over a few hundredths going from what we thought was a great set of headers to what we thought was the worst set of headers. I hope you have better luck chasing et with we exhaust than we did.
Last edited by hustlin hoosier; 09/05/16 09:26 PM.
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Re: How much are my small headers killing my performance
[Re: camastomcat]
#2148346
09/05/16 10:21 PM
09/05/16 10:21 PM
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Posts: 501 CEDAR RAPIDS
Plymouth340
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that's just it. I think they are considering the step headers that were on it when the previous owner was running it.. Converter is 7000 stall and motor makes peak hp at 9000
Last edited by Plymouth340; 09/05/16 10:23 PM.
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Re: How much are my small headers killing my performance
[Re: Plymouth340]
#2148764
09/06/16 01:27 PM
09/06/16 01:27 PM
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Joined: Oct 2007
Posts: 4,206 New York
polyspheric
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master
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Tried shortening the collector?
Boffin Emeritus
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Re: How much are my small headers killing my performance
[Re: Plymouth340]
#2148813
09/06/16 02:32 PM
09/06/16 02:32 PM
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Joined: Jan 2003
Posts: 14,499 So. Burlington, Vt.
fast68plymouth
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It's "900hp", what headers were on it when it made 900hp?
2800 lbs, 148mph shows 700hp on the moroso chart. Figuring 10% loss for air quality, parasitic losses, etc, you're still off over 100hp. I don't know if the headers would be worth that kind of power.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: How much are my small headers killing my performance
[Re: Plymouth340]
#2148916
09/06/16 04:25 PM
09/06/16 04:25 PM
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Joined: Jan 2003
Posts: 14,499 So. Burlington, Vt.
fast68plymouth
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At seasons end...... Might be worth a trip to the dyno and see just how much difference in power there is between the headers......before going through the effort of fitting them to the car.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: How much are my small headers killing my performance
[Re: camastomcat]
#2149020
09/06/16 06:44 PM
09/06/16 06:44 PM
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Joined: Jan 2003
Posts: 14,499 So. Burlington, Vt.
fast68plymouth
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Isn't Dwayne Porter a small block guy? Mmmmmmmm, not particularly. Never even laid my eyes on a W7 head in person.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: How much are my small headers killing my performance
[Re: Plymouth340]
#2149023
09/06/16 06:48 PM
09/06/16 06:48 PM
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Joined: Jan 2003
Posts: 14,499 So. Burlington, Vt.
fast68plymouth
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I need to talk to someone about it that knows more than me that's why I'm asking. Unless someone has tested a motor combo that's very close to yours with both sizes of headers you're talking about, and they're willing to share that info, you might have to test if for yourself to find out exactly what the answer is....... On your motor. 100+ hp seems like a stretch for a header swap to me....... But that's what the dyno is for. To provide answers to those questions.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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