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#1
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Headers or RARE o/s Manifolds
always used headers. have the rare round port o/s ported manifolds now. lucky to have grabbed a set it seems. was surprised at how close the data is below from a great article previously posted. hmmm seems tweaks in other areas, suspension/fuel delivery would easily make up the difference for quarter mile times. like the f.a.s.t. guys do.
455 Dyno Test Results With Compression Bent Exhaust Extensions Part Peak HP/RPM Peak Torque/RPM Avg. HP Avg. Torque Hedman 443 at 5,400 479 at 4,300 424 456 RARE Ram Air 423 at 5,300 471 at 4,300 409 439 Last edited by JUDGE3; 12-20-2023 at 10:51 AM. |
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#2
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Looking at your posted numbers and what is the most important in regards to over all performance is the average hp and Tq numbers .
The choice for me would be clear. Let’s look at just the rear wheel torque difference of let’s say a 3.00 ratio with no first gear factored in or torque converter multiplication. The header set up nets you 1368 ft lbs, and the manifolds net you 1317. 50 ft lbs is a big plus I would want at my right foots command ! Another way to look at it is that a extra 50 ft lbs makes up for your power losses of driving your water pump, Alt and power steering.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! Last edited by steve25; 10-18-2023 at 02:04 PM. |
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#3
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For a street car the RA/HO exhaust manifolds are a great option. Doesn't look like your giving up much. What is the combo?
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Tim Corcoran |
#4
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article
good article posted by zegermanham member.
headers always outperforms manifolds yes, I was just surprised at how close the manifolds are in comparison. figured a much bigger spread. https://www.motortrend.com/how-to/hp...-vs-manifolds/ (see if link works this time) Last edited by JUDGE3; 10-18-2023 at 05:29 PM. |
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#5
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I think Lee Atkinson here on his personal bone stock 455 TA on his own chassis dyno posted a bigger change when he swapped on
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#6
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SD performance have a good tech article on this topic. RARE OS manifolds can make almost as much power as headers. OR a lot less. Link below explains.
https://www.sdperformance.com/moreTech.php?newsID=39 |
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#7
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Seems to rely a lot on the combo. Paul did back to back dyno testing on a 500hp 455 with sd ported heads and Paul's custom hydraulic roller and the manifolds were within just 3-4 HP and actually made more average torque on that engine.
That engine was for a member here and there was a nice thread on it a few years ago with all the build details and the dyno sessions. |
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#8
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I think you are going to find it very combination specific on how much. Heck my 385-400 hp RAIV 400 liked smaller headers. My buddy's 455 E head ported by Dave and solid roller lost 40 hp on the dyno going from 2" to my 1 3/4-1 7/8 Hedmans. And an Edelbrock exhaust port is smaller than 1 3/4.
But looking at some of the cross sections of the RARE Paul used to bring to events they are pretty narrow.
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#9
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My recent chassis dyno results really has me rethinking my decision to stick with R/A manifolds. What are the cam specs and head flow combos that tend to benefit more headers vs. losing very little with manifolds?
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Ken '68 GTO - 464 - Ram Air II heads - 236/242 roller - 9.5” TSP converter - Moser 3.55 Truetrac (build thread | walk around) '95 Comp T/A #6 M6 - bone stock (pics) |
#10
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http://forums.maxperformanceinc.com/...ht=header+dyno
Lee's numbers
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#11
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Look up the "collector" on the top.
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#12
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Quote:
239/243 on a 112 lsa. The neat part is Paul posted the entire dyno graph back to back with headers and RA manifolds and they follow each other withing 3-4 HP and actually better torque with manifolds. Owner of the car used to post here, can't remember his name. |
#13
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Larry, believe its this Paul Carter build
SD CNC ported open chamber mod 670's on a 413 for James (vidguy).
Ended up being installed with 2.45" outlet RARE manifolds. Still impressed with this build! http://forums.maxperformanceinc.com/...d.php?t=795059
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Buzzards gotta eat... same as worms. |
#14
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intake manifold
currently have the performer rpm intake, what impact would moving to a torker2 single plane intake have in using the rare exhaust manifolds?
comp cams h/r cam: GRIND # P8 3317S /3318S HR110.0 Lunati 1.65 rockers DURATION @ .050 INTAKE 242 DURATION @ .050 EXHAUST 248 VALVE LIFT INTAKE .540 VALVE LIFT EXHAUST .562 LOBE SEPARATION 110.0 INTAKE C/L 106.0 |
#15
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My motor made 429hp/522 tq with RA manifolds and 439hp/519tq with headers. Personally, for a strictly street car, I don't think that's enough of a difference to deal with header hassles.
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70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share |
#16
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My mild 455 made 491 hp with hooker 1.75 headers and made 475hp with 2.25" ra manifolds with a 2.5" mandrel bent headpipe.
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72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007 (cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD 1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86' |
#17
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I dont believe anyone could feel 10 HP on a 500HP pontiac in the ass dyno!Tom
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#18
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On a flow bench. Would the exhaust port flow differently with a header tube and a manifold attached to the port? Would you then want to have a different exhaust lobe for headers verses a manifold?
Stan
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Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#19
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Correct me if I'm wrong, I didn't have a bunch of time to read these comments or the article. But it looks like most folks feel the headers aren't worth the bother over the RA manifolds. But there is a bigger gain with the headers compared to RA manifolds than there is with the RA manifolds compared to the logs.
Why are the RA manifolds worth the cost, two year wait time when you could lose less (than the difference between headers and RA manifolds) using log manifolds which usually can be had for free. |
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#20
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Your engine is probably the closest to mine in terms of configuration, although your aluminum heads flow more than my cast iron ones. I'm totally comfortable giving up 10hp. For headers to be compelling I'd probably want to see a 20+hp gain.
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Ken '68 GTO - 464 - Ram Air II heads - 236/242 roller - 9.5” TSP converter - Moser 3.55 Truetrac (build thread | walk around) '95 Comp T/A #6 M6 - bone stock (pics) |
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