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Whats the defference between cast exh manifold and HP #1684797 10/12/14 02:16 PM 10/12/14 02:16 PM
Joined: Jan 2013 Posts: 103 M.A. F Fern OP member
Fern OP member F Joined: Jan 2013 Posts: 103 M.A.	Not looking to go with headers, will HP manifolds make a big difference in performance. Its a 440. And what is different about them? Thanks

Re: Whats the defference between cast exh manifold and HP [Re: Fern] #1684798 10/12/14 02:59 PM 10/12/14 02:59 PM
Joined: Feb 2005 Posts: 4,313 Prospect, PA BSB67 master
BSB67 master Joined: Feb 2005 Posts: 4,313 Prospect, PA	As compared to what?

Re: Whats the defference between cast exh manifold and HP [Re: BSB67] #1684799 10/12/14 03:02 PM 10/12/14 03:02 PM
Joined: Jan 2013 Posts: 103 M.A. F Fern OP member
Fern OP member F Joined: Jan 2013 Posts: 103 M.A.	Quote: As compared to what? AS compared to the non HP stock manifolds. Sorry.

Re: Whats the defference between cast exh manifold and HP [Re: Fern] #1684800 10/12/14 03:51 PM 10/12/14 03:51 PM
Joined: Jan 2003 Posts: 2,530 Nunya CA CR8CRSHR master
CR8CRSHR master Joined: Jan 2003 Posts: 2,530 Nunya CA	Both types of manifolds are "Cast" pieces. The "stock logs" are not as performance oriented compared to the HP Manifold. Better flow out of the HP. I prefer the HP over Headers on a mostly street driven car. Back in the day they were really quite acceptable in those MOPAR Muscle Cars. Yet to the first thing yanked after the purchase of one of them was to replace them with Headers. Still I like the HP's...

Re: Whats the defference between cast exh manifold and HP [Re: CR8CRSHR] #1684801 10/12/14 05:16 PM 10/12/14 05:16 PM
Joined: Jan 2013 Posts: 103 M.A. F Fern OP member
Fern OP member F Joined: Jan 2013 Posts: 103 M.A.	What Im trying to find out is, how much better flow do you get from the HP manifolds as compared to the non HP. Or what is the horse power increase? if any. Did lots of searching but could only find comparisons from HP manifolds to headers, which I dont want. Thanks

Re: Whats the defference between cast exh manifold and HP [Re: Fern] #1684802 10/12/14 05:22 PM 10/12/14 05:22 PM
Joined: Apr 2012 Posts: 18,880 - R RSNOMO Moparts Torchbearer
RSNOMO Moparts Torchbearer R Joined: Apr 2012 Posts: 18,880 -	You want to maximize your cast-iron HP manifolds, get 'em extrude-honed...

Re: Whats the defference between cast exh manifold and HP [Re: RSNOMO] #1684803 10/12/14 05:26 PM 10/12/14 05:26 PM
Joined: Mar 2004 Posts: 2,963 Wisconsin Stewpar master
Stewpar master Joined: Mar 2004 Posts: 2,963 Wisconsin	Quote: You want to maximize your cast-iron HP manifolds, get 'em extrude-honed... That is A LOT of money for maybe 5-10 HP....... Stock HP manifolds are just fine. Admiration For Multiple Carburetor Vehicles...

Re: Whats the defference between cast exh manifold and HP [Re: Stewpar] #1684804 10/12/14 05:33 PM 10/12/14 05:33 PM
Joined: Jan 2003 Posts: 17,516 Las Vegas, NV 6bblgt I Live Here
6bblgt I Live Here Joined: Jan 2003 Posts: 17,516 Las Vegas, NV	& the real question appears to be: How much do I need to spend? A) $50 pair of "log" manifolds B) $350 pair of dual exhaust/HP manifolds C) $500+ pair of quality headers & what are the horsepower consequences? as always more information is needed: What kind of vehicle & what's in your 440 build? What are your intended uses with said vehicle?

Re: Whats the defference between cast exh manifold and HP [Re: Fern] #1684805 10/12/14 05:37 PM 10/12/14 05:37 PM
Joined: Dec 2004 Posts: 10,553 Rittman Ohio fourgearsavoy I Live Here
fourgearsavoy I Live Here Joined: Dec 2004 Posts: 10,553 Rittman Ohio	All you really need to do is look at them side by side and you can easily see which exhaust would flow better Are you actually looking for dyno numbers? AndyF has done some real world testing on HP manifolds and had some surprising horsepower figures but also noted that some custom ground cams would be required to optimize the cast iron HP manifolds. You can use the custom Google search at the top of the page for more info. Gus 8298232-rearviewsavoy.jpg (134 downloads) 64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60

Re: Whats the defference between cast exh manifold and HP [Re: fourgearsavoy] #1684806 10/12/14 05:57 PM 10/12/14 05:57 PM
Joined: Jan 2003 Posts: 3,575 The Netherlands BigBlockMopar master
BigBlockMopar master Joined: Jan 2003 Posts: 3,575 The Netherlands	I recall one of the magazines had done some testing on the manifolds and the outcome was that there were just minor differences between the HP's and the stockers. The manifold exit diameter was the most telling how well a manifold performed I recall but the didn't come close to a simple shorty header. I think I have it bookmarked somewhere. BigBlockMopar.com

Re: Whats the defference between cast exh manifold and HP [Re: BigBlockMopar] #1684807 10/12/14 06:17 PM 10/12/14 06:17 PM
Joined: Jan 2003 Posts: 3,575 The Netherlands BigBlockMopar master
BigBlockMopar master Joined: Jan 2003 Posts: 3,575 The Netherlands	Here's an article of Steve Dulcich; http://www.moparmusclemagazine.com/techarticles/mopp_0106_manifolds_vs_headers/ Here's one from Panic on how to modify manifolds; http://victorylibrary.com/mopar/ci-man-tech-c.htm BigBlockMopar.com

Re: Whats the defference between cast exh manifold and HP [Re: BigBlockMopar] #1684808 10/12/14 08:12 PM 10/12/14 08:12 PM
Joined: Feb 2010 Posts: 18,493 Granite Bay CA Kern Dog Striving for excellence
Kern Dog Striving for excellence Joined: Feb 2010 Posts: 18,493 Granite Bay CA	Not a direct comparison, BUT... The TNT 440 in the 67 Chrysler 300 was essentially a 440 Magnum. It used the same style "Magnum" manifolds with dual exhaust, the same intake, carburetor and camshaft. It also had a windage tray. The 440 "Magnum/Super Commando/TNT" was rated at 375 HP. The base 440 in the 67 Chrysler and other models used a log type exhaust manifold, a Y pipe into a single exhaust pipe and a milder cam. It was rated at 350 HP. The 25 HP difference is attributed to the cam, exhaust and windage tray. Its safe to figure that 8-10 HP could be from the exhaust system.

Re: Whats the defference between cast exh manifold and HP [Re: Kern Dog] #1684809 10/16/14 07:11 AM 10/16/14 07:11 AM
Joined: Jan 2005 Posts: 4,862 the frozen wastes... Pale_Roader Swears too much
Pale_Roader Swears too much Joined: Jan 2005 Posts: 4,862 the frozen wastes...	Quote: Not a direct comparison, BUT... The TNT 440 in the 67 Chrysler 300 was essentially a 440 Magnum. It used the same style "Magnum" manifolds with dual exhaust, the same intake, carburetor and camshaft. It also had a windage tray. The 440 "Magnum/Super Commando/TNT" was rated at 375 HP. The base 440 in the 67 Chrysler and other models used a log type exhaust manifold, a Y pipe into a single exhaust pipe and a milder cam. It was rated at 350 HP. The 25 HP difference is attributed to the cam, exhaust and windage tray. Its safe to figure that 8-10 HP could be from the exhaust system. While its nice and fun to bench race like this... with Mopar you cannot even begin to use factory ratings for comparisons. Not even in the vicinity ov 'close'. The TNT never made that 375 and the stock 440 never even came close to 350. I would agree though that from most ov my reading (thats a lot), the HP iron would probably make about that difference, give or take... but also vastly dependent on the build too. The numbers some guys (F.A.S.T.) are getting from HP manifolds is utterly obscene, but there is a LOT ov voodoo going on there obviously... I will say from experience that on big block Mopars, the difference between a log and an HP manifold is a lot closer than the difference between the HP and even a cheap 'bad' header. I've wanted to go back to manifolds forever too... but thats just too big a hit for me to take. NOTHING wakes a Mopar big block up like headers... that should tell you something. Some makes you can add headers and its just not worth the hassle at all. Maybe just head down to the local Pick a Part and score some Max Wedge manifolds...

Re: Whats the defference between cast exh manifold and HP [Re: Pale_Roader] #1684810 10/16/14 07:15 AM 10/16/14 07:15 AM
Joined: Jan 2005 Posts: 4,862 the frozen wastes... Pale_Roader Swears too much
Pale_Roader Swears too much Joined: Jan 2005 Posts: 4,862 the frozen wastes...	Is there a specific reason why you dont want headers? If its the usual header BS, then how about Schumacher engine swap headers? Maybe not the best performing, but still WAY better than iron, and no install hassles, no leak hassles, no header sound and no clearance hassles. VERY nice quality looking pieces too. Unless its about visuals, like staying OEM, or maybe building a sleeper, the Schumachers cover a LOT ov bases.

Re: Whats the defference between cast exh manifold and HP [Re: Pale_Roader] #1684811 10/16/14 08:23 AM 10/16/14 08:23 AM
Joined: Jan 2003 Posts: 10,714 North Dakota 6PakBee I Live Here
6PakBee I Live Here Joined: Jan 2003 Posts: 10,714 North Dakota	Looking at the Dulcich article I found it interesting that the HP difference at 3000 was about 16 and at 5800 was about 75. If the test had been done with a 383 with the lower exhaust flow, would there have been any difference at all? "We live in a time when intelligent people are being silenced so that stupid people won't be offended".

Re: Whats the defference between cast exh manifold and HP [Re: Fern] #1684812 10/16/14 11:41 AM 10/16/14 11:41 AM
Joined: Oct 2011 Posts: 559 Idaho L LaRoy Engines mopar
LaRoy Engines mopar L Joined: Oct 2011 Posts: 559 Idaho	I personally tested the log manifold vs the HP manifold on a 300 horsepower 440. We gained a whole 4 horsepower when we installed the HP manifolds. Last edited by LaRoy Engines; 10/16/14 11:43 AM.

Re: Whats the defference between cast exh manifold and HP [Re: LaRoy Engines] #1684813 10/16/14 11:59 AM 10/16/14 11:59 AM
Joined: Jan 2003 Posts: 75,008 U.S.S.A. JohnRR I Win
JohnRR I Win Joined: Jan 2003 Posts: 75,008 U.S.S.A.	Quote: I personally tested the log manifold vs the HP manifold on a 300 horsepower 440. We gained a whole 4 horsepower when we installed the HP manifolds. What size headpipes did you use with each set of manifolds? One of the main differences is the outlet on the HP manifold is almost 2.5" , the log is I am pretty sure 2". the question the OP needs to ask himself is the extra money to switch to the HP manifolds , in both the cost of the manifolds and the cost of the exhaust system change worth it to him ? Some people just don't want to deal with the headaches involved with headers on a car that may only see the track , for fun and little else , maybe once or twice , a year ... or ever ... But the OP never said what car he has ...

Re: Whats the defference between cast exh manifold and HP [Re: 6PakBee] #1684814 10/16/14 08:07 PM 10/16/14 08:07 PM
Joined: Feb 2005 Posts: 4,313 Prospect, PA BSB67 master
BSB67 master Joined: Feb 2005 Posts: 4,313 Prospect, PA	Quote: Looking at the Dulcich article I found it interesting that the HP difference at 3000 was about 16 and at 5800 was about 75. If the test had been done with a 383 with the lower exhaust flow, would there have been any difference at all? I think the manifold portion of the article is worthless. The manifolds were open.

Re: Whats the defference between cast exh manifold and HP [Re: 6PakBee] #1684815 10/16/14 09:53 PM 10/16/14 09:53 PM
Joined: Jun 2012 Posts: 1,386 Philadelphia PA Pynzo Drugs are bad
Pynzo Drugs are bad Joined: Jun 2012 Posts: 1,386 Philadelphia PA	Quote: Looking at the Dulcich article I found it interesting that the HP difference at 3000 was about 16 and at 5800 was about 75. If the test had been done with a 383 with the lower exhaust flow, would there have been any difference at all? With the right exhaust-yes. Going from ('70 383 Magnum) headers and 2-1/2" exhaust, turbo mufflers, to stock HP manifolds and new TTI 2-1/2 exhaust- same performance without the burnt ignition wires, clearance for everything hassle of headers. I love the sound of a stock Mopar starter. Newer headers I looked at required mini starters. Edit- No Dyno No Computer tests It's what I feel in my gas pedal foot and by the way my head snaps back when I mash down the gas pedal- Last edited by Pynzo; 10/16/14 09:58 PM.

Re: Whats the defference between cast exh manifold and HP [Re: BigBlockMopar] #1684816 10/16/14 10:45 PM 10/16/14 10:45 PM
Joined: Jun 2012 Posts: 1,386 Philadelphia PA Pynzo Drugs are bad
Pynzo Drugs are bad Joined: Jun 2012 Posts: 1,386 Philadelphia PA	Quote: Here's an article of Steve Dulcich; http://www.moparmusclemagazine.com/techarticles/mopp_0106_manifolds_vs_headers/ Here's one from Panic on how to modify manifolds; http://victorylibrary.com/mopar/ci-man-tech-c.htm If you read this article and want custom carbide burrs- I have been making them for almost 30 years. Any shape, cut, or shank(solid or flex) length. I also repair used broken burrs. Just Sayin.

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