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headers v free flow
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hacksaw1971 View Drop Down
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Points: 1401 		Post Options Post Options   Thanks (0) Thanks(0)   Quote hacksaw1971 Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2022 at 3:59pm
Originally posted by BU1 BU1 wrote:

I don't understand the appeal of headers on most street driven cars. They hang low, leak, make changing starters an Olympic event,.................  How much driving do you do at 5k rpm?  Help me understand.
  she will see some track time but ain't going to live there. but she won't be stock nether... lot of head work nice street/strip cam airgap good gears. hoping to make 400-ish.  but ya .. i hate headers but i like a nice flat TQ curve more...
its the little things that make the biggest difference
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Points: 5799 		Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2022 at 5:34pm
Originally posted by Trader Trader wrote:

This was done back in 2012, and the more RPM you add the better long tube headers will perform. Believe you should cut your expectations in half unless well built for racing and seeing 6000+ RPM a lot:

We ran a series of dyno test on my 401 yesterday.  Here are the results of the free flow (massaged) manifolds, Edelbrock shortys, and long tube headers.
 
Manifolds - 366.2 hp and 401 torque @ 5050 rpm
 
Edelbrock shortys - 368.7 hp and 412 torque @ 5250
 
Long tube headers - 382 hp and 430 torque @ 5050
 
The test was conducted by SC397.
 
Needless to say we are leaving alot of hp and torque untapped by the use of the manifolds but there is not enough gain by using the shortys.  Also the long tubes will not work on my car due to how low the car sets.

I would like to see the curves as well as the peak numbers, I believe long tube headers will pick up power and torque right across the rev range, not just at the top.

In my experience, I went from 13.6 @ 99 mph to 12.6 @ 109 mph by adding headers, however this did also include replacing a very old and restrictive exhaust system with 3" pipes dumping at the diff. 
I've finally given up drinking for good...........now I only drink for evil.
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hacksaw1971 View Drop Down
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Points: 1401 		Post Options Post Options   Thanks (0) Thanks(0)   Quote hacksaw1971 Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2022 at 5:54pm
Originally posted by WesternRed WesternRed wrote:

Originally posted by Trader Trader wrote:

This was done back in 2012, and the more RPM you add the better long tube headers will perform. Believe you should cut your expectations in half unless well built for racing and seeing 6000+ RPM a lot:

We ran a series of dyno test on my 401 yesterday.  Here are the results of the free flow (massaged) manifolds, Edelbrock shortys, and long tube headers.
 
Manifolds - 366.2 hp and 401 torque @ 5050 rpm
 
Edelbrock shortys - 368.7 hp and 412 torque @ 5250
 
Long tube headers - 382 hp and 430 torque @ 5050
 
The test was conducted by SC397.
 
Needless to say we are leaving alot of hp and torque untapped by the use of the manifolds but there is not enough gain by using the shortys.  Also the long tubes will not work on my car due to how low the car sets.

I would like to see the curves as well as the peak numbers, I believe long tube headers will pick up power and torque right across the rev range, not just at the top.

In my experience, I went from 13.6 @ 99 mph to 12.6 @ 109 mph by adding headers, however this did also include replacing a very old and restrictive exhaust system with 3" pipes dumping at the diff. 
 i do have 2.5 duals with flow thro muffs. just doing that not long before i took the mill out made a BIG change.   but im more into the whole power curve myself. like with the intake.  airgap and 1 in open spacer is much more better than the torker will ever be across the curve and is flat as glass from like 2200 and is within 5 hp and like 15 tq's at 6500. (engine masters test of intake and spacer)
its the little things that make the biggest difference
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mbwicz View Drop Down
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Points: 1989 		Post Options Post Options   Thanks (1) Thanks(1)   Quote mbwicz Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2022 at 6:29pm
  This thread is a good example of why this forum is great.  A gent asked a question, someone referred to a similar thread from years ago.  Others give their opinions and share their data, and people are allowed to make their own decision and build what they want.  No arguments, no name calling, just AMC enthusiasts sharing.
  Myself, I have a 390 with E-heads, Pro-flow, and a roller cam.  I decided to go with ARH headers and exhaust.  Time will tell if I'm happy or not....

Mike
1970 AMX, one step forward, one step back. Both steps cost time and money.
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Points: 5799 		Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2022 at 7:25pm
ARH are on my wish list, I only have some old Hedmans on it now and they are pretty poorly made, especially the silly weld bead around the exhaust port that doesn’t match anything. Had to spend a fair bit of time recently adding more weld and file finishing it to get a decent seal. I’m trying some SCE copper gaskets, but there is no way they were going to work without fixing the headers first.
I've finally given up drinking for good...........now I only drink for evil.
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Points: 7949 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2022 at 7:27pm
Originally posted by mbwicz mbwicz wrote:

  This thread is a good example of why this forum is great.  A gent asked a question, someone referred to a similar thread from years ago.  Others give their opinions and share their data, and people are allowed to make their own decision and build what they want.  No arguments, no name calling, just AMC enthusiasts sharing.
  Myself, I have a 390 with E-heads, Pro-flow, and a roller cam.  I decided to go with ARH headers and exhaust.  Time will tell if I'm happy or not....

Mike
Supposed to be the very best headers on the market. I had a set of headers once on a 454 Corvette that I didn't find objectionable. They didn't leak and they didn't drag. They tucked up pretty well as do the ARH from what I know about them. Hope they work out. 
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Gench View Drop Down
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Points: 182 		Post Options Post Options   Thanks (1) Thanks(1)   Quote Gench Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2022 at 8:20pm
ARH headers on my 70 - thick head flanges and modern connections should fix most of the woes of the old headers.  
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Points: 204 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Regamble1969 Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2022 at 9:21pm
Originally posted by WesternRed WesternRed wrote:

ARH are on my wish list, I only have some old Hedmans on it now and they are pretty poorly made, especially the silly weld bead around the exhaust port that doesn’t match anything. Had to spend a fair bit of time recently adding more weld and file finishing it to get a decent seal. I’m trying some SCE copper gaskets, but there is no way they were going to work without fixing the headers first.

I'm actually in a similar situation. I have a 69 with rectanglular port heads. Bought a set of NOS hedmans that didn't seem to fit right. I made some adjustments and tweaks at first. The original flange opening was 1/4" off on one port, too small on another etc...  I'm just at the point that I've completely cut them down to just the flanges and I'll build my own. Enough is enough. Build a rectangular wedge to form the entry points, rotary file to match port the flanges to the heads. Oh the joys.
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hacksaw1971 View Drop Down
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Points: 1401 		Post Options Post Options   Thanks (0) Thanks(0)   Quote hacksaw1971 Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2022 at 9:26pm
Originally posted by Gench Gench wrote:

ARH headers on my 70 - thick head flanges and modern connections should fix most of the woes of the old headers.  




holy heck ... 1800 bucks???  thay better put them selfs in ....lol
its the little things that make the biggest difference
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Trader View Drop Down
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Points: 6881 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: May/24/2022 at 9:28pm
Have seen the ARH headers on one car so far. They look pretty darn good compared to the older offerings.
Well built, well fit, good materials.
If the build requires, budget permits, brain bling wants headers - these are what to use. most everything else will just be grief in short order.
Ported free flows and 2" to 2-1/2" dual SS exhaust will do 90% of us hobbyist's.
Would not waste time on older galvanized pipes. Even modern cars use SS to last 10+ years.
Remember the old days of replacing exhaust components every 2 -3 years. The rusted fasteners that had to be cut off, rotted pipes, holy mufflers, rust in your face, wrapping gas lines so they would not get hit by sparks from grinder or torch!
The wife complaining about the disaster of the trail though the house and the shower. Let alone the rust stain on the white wash cloth or towel. Who in their right minds decided wash cloths and towels should be white???
The absolute dread of these old pieces of junk. Gone the good old days on this one, and happy to see them gone:)
 
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