Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: Cab_Burge]
#2572468
11/01/18 12:58 AM
11/01/18 12:58 AM
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Joined: Mar 2009
Posts: 2,475 Sydney,Australia
tex013
top fuel
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top fuel
Joined: Mar 2009
Posts: 2,475
Sydney,Australia
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The last pump gas 472 C.I. hemi motor I dyno tested in SO CA on a DTS engine dyno at Vrbancic Bros. in Ontario, CA did a little bit better, 625 HP @ 6200 RPM) than theirs did yeah numbers seem a little disappointing . Tex
New best ET 10.259@129.65 . New best MPH 130.32 Finally fitted a solid cam, stepped it up a bit more 3690lbs through the mufflers New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm Power by Tex's Automotive
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Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: DaveRS23]
#2572476
11/01/18 01:26 AM
11/01/18 01:26 AM
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Joined: Jan 2003
Posts: 7,498 Minnesota
Hemi_Joel
master
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master
Joined: Jan 2003
Posts: 7,498
Minnesota
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The dyno testing I did when I was developing my fast motors does not agree with there's whatsoever. 612 versus 588 horse, and 795 vs 762 horsepower. Nicks Hemi seemed to stumbled at the top end of the pull with the manifolds. I wonder if something was going away, or if the jetting was off?
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
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Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: DaveRS23]
#2572482
11/01/18 01:45 AM
11/01/18 01:45 AM
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Joined: Jun 2014
Posts: 5,183
Porter67
master
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master
Joined: Jun 2014
Posts: 5,183
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Nice numbers for a semi mild small block stroker, but a 472 hemi? Watch this vid and to me it tells so so much. https://www.youtube.com/watch?v=2SbInV5RVM8
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Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: Hemi_Joel]
#2572523
11/01/18 11:00 AM
11/01/18 11:00 AM
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Joined: Aug 2003
Posts: 8,779 Mt.Gilead, Ohio
OhioMopar
master
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master
Joined: Aug 2003
Posts: 8,779
Mt.Gilead, Ohio
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The dyno testing I did when I was developing my fast motors does not agree with there's whatsoever. 612 versus 588 horse, and 795 vs 762 horsepower. How? Cam selection? Better suited to the manifolds?
1969 Dart GTS 340 1969 Super Bee X9 N-96 1969 Coronet R/T X9 N-96 2015 Dodge Dart GT 2019 Ram 2500 Big Horn. Looking for the original block for my Bee. The last 4 are 7449
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Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: Porter67]
#2572553
11/01/18 12:25 PM
11/01/18 12:25 PM
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Joined: Feb 2006
Posts: 1,051 The Great White North
RAMM
super stock
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super stock
Joined: Feb 2006
Posts: 1,051
The Great White North
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What does it tell you? J.Rob
2009 PHR\EMC Competitor 2010 PHR\EMC Competitor 2011 PHR\EMC Competitor 2012 PHR\EMC Competitor 2013 PHR\EMC Competitor 2014 HotRod/EMC Competitor 2015 HotRod/EMC NoShow 2016 HotRod/EMC 3rd place SPEC Bigblock 2018 HotRod/EMC 7th place G3
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Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: 73DAD]
#2572554
11/01/18 12:29 PM
11/01/18 12:29 PM
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Joined: Feb 2006
Posts: 1,051 The Great White North
RAMM
super stock
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super stock
Joined: Feb 2006
Posts: 1,051
The Great White North
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He said they had problems with that engine that cut down the power. 80 lbs of spring pressure on the seat. I watched one of his vids with a G2 that had a misfire and rough idle for a few seconds after a pull. They could find nothing wrong and deduced it was a pushrod problem? I called him the next day and told him if he looked at his VE% numbers it would read abnormally high like in the +hundreds of percents maybe 700-800%. I pretty much guarantee he had an exhaust valve seizing open. He didn't believe me I don't think. Swore the pushrods fixed it. J.Rob
2009 PHR\EMC Competitor 2010 PHR\EMC Competitor 2011 PHR\EMC Competitor 2012 PHR\EMC Competitor 2013 PHR\EMC Competitor 2014 HotRod/EMC Competitor 2015 HotRod/EMC NoShow 2016 HotRod/EMC 3rd place SPEC Bigblock 2018 HotRod/EMC 7th place G3
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Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: DaveRS23]
#2572580
11/01/18 01:59 PM
11/01/18 01:59 PM
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Joined: Jan 2003
Posts: 14,514 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,514
So. Burlington, Vt.
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Take the same motor, test it with two different cams, and try the headers and manifolds with both cams. One cam, manifold friendly, one cam more of a typical mid-level bracket race cam that needs headers........ and you’re going to see a big difference in the spread in power output between the manifolds vs headers with the two different cams.
Trying to come up with a blanket figure to say headers are worth “xx” power over manifolds is kinda pointless. It’s absolutely one of those “it depends” things.
Someone here recently tested a 505 with TF240 heads and observed a 90hp difference.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: DaveRS23]
#2572691
11/01/18 06:08 PM
11/01/18 06:08 PM
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Joined: Jan 2003
Posts: 7,498 Minnesota
Hemi_Joel
master
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master
Joined: Jan 2003
Posts: 7,498
Minnesota
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You guys are dead on, as usual. In my F.A.S.T. builds it was known that the class rules required factory intake and exhaust manifolds, and a 2.5" exhaust system to the rear bumper. Cam profiles were selected accordingly. The same motor with a radically different cam would have different results in a manifold vs header comparison.
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
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Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: Hemi_Joel]
#2719464
11/26/19 01:36 PM
11/26/19 01:36 PM
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Joined: May 2019
Posts: 714 Lake Villa Il
INTMD8
super stock
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super stock
Joined: May 2019
Posts: 714
Lake Villa Il
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The dyno testing I did when I was developing my fast motors does not agree with there's whatsoever. 612 versus 588 horse, and 795 vs 762 horsepower. Nicks Hemi seemed to stumbled at the top end of the pull with the manifolds. I wonder if something was going away, or if the jetting was off? Bringing this back from the dead. The 612 vs 588 horsepower, was that on as-cast or ported manifolds? Trying to decide between headers and porting my manifolds. Thanks!
69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 650rwhp @7250 510rwtq @5700
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Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: INTMD8]
#2719541
11/26/19 07:39 PM
11/26/19 07:39 PM
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Joined: Jan 2003
Posts: 12,301 Benton, IL.
DaveRS23
OP
Special needs idiot
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OP
Special needs idiot
Joined: Jan 2003
Posts: 12,301
Benton, IL.
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When I was deciding on the final pieces for my 540 Hemi, I spoke to Indy about the exhaust. I was considering the 2 1/8 rather than the 2 1/4 TTIs. But they told me that the Hemis did not like any exhaust restrictions. So I have the 2 1/4 tubes and 3" straight thru exhaust with electric cut-outs. I have not experimented with the exhaust to know what works or what doesn't. Just passing along some advice I got from someone that probably knows what they are talking about.
Master, again and still
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Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: dthemi]
#2719694
11/27/19 11:15 AM
11/27/19 11:15 AM
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Joined: Nov 2003
Posts: 5,160 Texas
dannysbee
master
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master
Joined: Nov 2003
Posts: 5,160
Texas
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With out a doubt it’s not everyone’s cup of tea. But to some, me included, like a stock looking muscle car that performs better than expected. There were a couple of thing here that made this an awful comparison. One there was no tuning done after the switch to manifolds. The jetting will not be the same for both. The other thing is look at the exhaust on both set up. It’s clear that it was pretty much open headers on the Hemi but was run through 2.5 inch exhaust pipes on the manifolds. I’m not saying the manifolds will perform with the headers but the playing field was definitely tilted in this comparison.
Getting old just means you were smarter than some and luckier than others.
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Re: Cool shootout; 472 HEMI Stroker - Headers VS Manifolds
[Re: dannysbee]
#2719778
11/27/19 03:27 PM
11/27/19 03:27 PM
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Joined: May 2019
Posts: 714 Lake Villa Il
INTMD8
super stock
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super stock
Joined: May 2019
Posts: 714
Lake Villa Il
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^ Yes, obviously the headers will outperform the manifolds, that in itself is not the question but to what degree is.
Right now I have manifolds that fit perfectly and bolt up to my exhaust with no rattles/leaks/problems so for those reasons it's tempting to re-use them with some port work.
Nothing crazy, all iron 426.
Would I leave 50hp on the table? No, but if the 24hp example above was with untouched manifolds and that differential could be brought closer to 20 with port work or even welding I would certainly consider that option.
69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 650rwhp @7250 510rwtq @5700
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