[dana44]

Yes, yes they are. Take and look at a majority of the tests done with stock manifolds and headers, compare them, and you will see a pattern of gains at the higher rpm every time, even the bad headers out there. At the same time, look at where they compare to mandrel bent dual exhaust with H pipe or X pipe on stock manifolds and you will see that at normal cruising rpm, the increase over stock is little to no improvement, being the curve below 3000rpm in most cases. I find that you can get a little more improvement over porting the exhaust manifolds themselves, clean them up a bit and open the dump itself is a good savings of $150-800 UNLESS YOU ARE GOING TO BE RACING OR ROUTINELY RUN ABOVE THE 3000RPM RANGE, WHERE HEADERS START TO SHINE.

Not saying headers are a bad thing, just saying on street applications and normal driving/cruising on the highway, the gain is not worth the cost. Shorty headers are a good replacement for some of the stock exhaust manifolds, at least you don't have as great a volume of heat or road rash/leaks, etc..

 

[MoparNorm]

Yes, yes they are. Take and look at a majority of the tests done with stock manifolds and headers, compare them, and you will see a pattern of gains at the higher rpm every time, even the bad headers out there. At the same time, look at where they compare to mandrel bent dual exhaust with H pipe or X pipe on stock manifolds and you will see that at normal cruising rpm, the increase over stock is little to no improvement, being the curve below 3000rpm in most cases. I find that you can get a little more improvement over porting the exhaust manifolds themselves, clean them up a bit and open the dump itself is a good savings of $150-800 UNLESS YOU ARE GOING TO BE RACING OR ROUTINELY RUN ABOVE THE 3000RPM RANGE, WHERE HEADERS START TO SHINE.
Not saying headers are a bad thing, just saying on street applications and normal driving/cruising on the highway, the gain is not worth the cost. Shorty headers are a good replacement for some of the stock exhaust manifolds, at least you don't have as great a volume of heat or road rash/leaks, etc..

Since you are crapping in my bed, I'll just say that I respectfully disagree. Not my headers that I design and build.
Tried to tell you in the previous post, my headers are tuned for low to midrange torque and dyno with a 21% improvement in torque and horsepower in that range.
I've spent the last 11 years overturning old fashioned assumptions like that one.
You don't need to write in capitols, to discount my data.

 

[dana44]

OK, I concede. Yes, there are headers that can do better at low rpm, which is possible, but not out of the box. I am glad someone (yourself in this case), that has made a header that works better at lower rpm. Didn't say it wasn't possible, just that the $150 headers you get off the shelf in a big cardboard box are cheap, designed to work above 4500rpm (where a person rarely drives), and leak fromt the second day they are installed. Mopars are notorious for having road rash with the exception of TTi headers, the owners up in Corona are Mopar only guys and they have an excellent product, met them way back when they first started, great guys, their headers always always always win any comparison with the competition, and they are on the high end of $600-800 for a set. Worth it, yes, but not for the novice to install (perfect fit every time, never road rash, but a little expensive for a person making minimum wage, you have to save up to afford them, and worth it in my opinion). A person adding headers to think they are going to gain more power for normal day to day driving, port the heads, the flow to the exhaust manifolds is definitely going to be worth more than the cost and headaches.

Now, what headers are you making? Jeeps, I take it? You never said anything before, I did not know.

Oh, and the capitals were not necessarily for you, but for those making the big bucks decision to have the header headaches and leaks for such a low gain if just a daily driver. A mandrel bent exhaust the size of the exhaust manifold dump 90 percent of the time (5 percent for yours, 5 percent for TTi) are the exceptions.

 

[MoparNorm]

Stereotypes aside:
My headers are very specialized, only for the Poly 318 and only for the 1961-1971 Sweptline's and Townies. I have a modified sets that fit the Poly head in the 1946 to 1958 WDX-WD300 Power Wagons as well.
TTI is OK, they compete with me and in fact lowered their price as soon as I started selling. I first went to them about 15 years ago and they blew me off, so I started making my own.
My headers do not rub, drag, come loose, or crack. They are heavy wall, thick flanged, ceramic coated with ARP bolts and great laser cut gaskets. They are superior to TTI.
Oh, and thanks for discouraging folks from buying them, not only did you discourage them, you then sent them to my competition.

Seriously, they aren't a fit for the LA block in this thread, so it's not a conflict of interest for me to talk about something I know.
When you finish porting your heads, your engine is still incomplete, without a good set of headers.
Exhaust is in fact so important, that Chrysler no longer makes exhaust manifolds for the Pentastar, they are cast into the head as one piece, to prevent the aftermarket from messing up the scavenging effect.

 

[dana44]

Sorry Norm. Didn't mean to mess with your business whatsoever. A ply only set of headers is a pretty small market, and if it is any consolation, headers that are tuned properly to replace manifolds that are superior to the flow of stock manifolds, then you have improved over stock. Except for the B/RB ramhorn manifolds, I am positive your manifolds are better than stock, need to now start making them to replace the LA block manifolds. Stock manifolds can be improved upon, yes, mass production headers aren't the ticket for most, but 11 years of work probably pays off more than the old designs that have been around since I started running the occasional header.Poly manifolds were part of that horrible log style that wasn't known for racing.

 

[MoparNorm]

It's a tad better than the logs...

 

[dana44]

Norm, those look great, and in this case, yes, this design is really good for building the bottom end torque you have worked on. Compare these to the nasty stock manifolds and the aftermarket where they are four long tubes, yes, this design does help breathe and at the same time improve the bottom end torque. Yes, I would recommend these as a header replacement for stock exhaust manifolds, Tompson (I believe) tri-Y design is one of the higher priced alternatives, If I build a Poly, expect me to get ahold of you. Any plans for an LA design like this?

 

[MoparNorm]

Thanks Dana!
I do not have plans for the LA block, simply because of the reasons you stated. There are a ton of cheap, inexpensive units out there and to raise above the din takes more marketing horsepower than I have. ; )

 

[dana44]

I hear you. Any plans for future engines? Thinking 2.2/2.5......for my NA Triumph TR-4 when I get to work on her. Long tube headers just don't do it for the street.

 

[MoparNorm]

Never know when the need will pop up. It's usually some obscure motor that a handful of guys start asking for..
For example, to keep out of the poor house I needed 50 orders to break even on the Poly headers.
I got 75 orders!
So then I asked for deposits... :lol:
I got 35, I milked it to 40 orders and stuck my neck out.
Six years later I just shipped # 68.
It's love, not profit.

 

[dana44]

I hear you. Good deal all the way around.