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My combo needs a set of long tubes. My goal is to put over 500hp to the rear wheels on my Procharged 96 LT4. If you haven't seen my build thread I am doing a complete H/C/I, brake upgrade, suspension re-fresh, fuel system, etc. to support. I do plan on keeping my Corsa cat-back. I had earlier set my eyes on a set of ARH, but before I pull the trigger I want to see some feedback on:
What is the best to put on for a 500hp car. Most of the information I have seen are guys putting them on relatively stock cars. How about fit, spark plug clearance, what works best with AFR heads?
I am also considering investing in getting them coated. Has anyone had their ARH set coated?
My combo needs a set of long tubes. My goal is to put over 500hp to the rear wheels on my Procharged 96 LT4. If you haven't seen my build thread I am doing a complete H/C/I, brake upgrade, suspension re-fresh, fuel system, etc. to support. I do plan on keeping my Corsa cat-back. I had earlier set my eyes on a set of ARH, but before I pull the trigger I want to see some feedback on:
What is the best to put on for a 500hp car. Most of the information I have seen are guys putting them on relatively stock cars. How about fit, spark plug clearance, what works best with AFR heads?
I am also considering investing in getting them coated. Has anyone had their ARH set coated?
I do not think you have much of a choice left other than ARH at this point...
My combo needs a set of long tubes. My goal is to put over 500hp to the rear wheels on my Procharged 96 LT4. If you haven't seen my build thread I am doing a complete H/C/I, brake upgrade, suspension re-fresh, fuel system, etc. to support. I do plan on keeping my Corsa cat-back. I had earlier set my eyes on a set of ARH, but before I pull the trigger I want to see some feedback on:
What is the best to put on for a 500hp car. Most of the information I have seen are guys putting them on relatively stock cars. How about fit, spark plug clearance, what works best with AFR heads?
I am also considering investing in getting them coated. Has anyone had their ARH set coated?
i have the arh 1 3/4 to 1 7/8” stepped coated headers and their x pipe mated to rear portion of stock exhuast (with dynomax’s unique for corvette lt1 super turbo mufflers).
fit was ok, but not as good as the prior tpis 1 3/4” long tube headers i had.
I had issues clearing my canton road race oil pan with swingouts. I had to put 1/8” shim spacers off the head to get the bottom of the tube to clear the swingouts and even then its close.
*note the tpis 1 3/4” long tubes fit around that pan fine*
the arh headers were quite a bit heavier as well. They get a real boner bragging how their flange is ‘extra thick’, but thats just extra weight and extra frustration during spark plugs changes. Im not aware of what ‘if any’ performance benefits ‘extra thick’ mounting flange gives. Just a weight-adder
spark plug changes are still way easier than stock manifolds but not as easy as with the tpis 1 3/4” headers i had before
i had the swain tech coating - it has held up well
overall im happy. They added an extra 2 o2 bungs for me for wideband o2 sensors. This is on my 93 lt1
I have the ARH stepped headers; 1 3/4” to 1 7/8”. They were worth .15 seconds over hooker 1 3/4”. They are very well made and fit well with my 7qt Moroso pan. To reply to the above post, thicker flanges mean less warpage and better sealing; not necessarily a direst performance gain
Stainless works are 1 5/8 IIRC. They are their own company. Summit is just selling them. Both companies are local to me. I bought ARH's for my 96. They are still in the box. Stainless Works wanted to use my car to determine fitment and placement of their O2 bungs. They offered me a "deal". Which would have cost me 100's more, including my time than if I had bought them from Zip Corvette and installed myself.
100's more to do them a favor. I told them to pound it.
The best headers for a boosted car are the ones that flow the most. The blower will dominate any exhaust scavenging effects of the headers. Having said that, 500 hp seems awfully conservative for a boosted engine. Still running the stock LT4 heads?
The best headers for a boosted car are the ones that flow the most. The blower will dominate any exhaust scavenging effects of the headers. Having said that, 500 hp seems awfully conservative for a boosted engine. Still running the stock LT4 heads?
Which one flows the best?
AFR 210's with a LE Port Job, LE Cam, and 8PSI to start.
I went with Stainless Works for the 96 I built. I looked at ARH, but couldn't justify the price jump to get the ARH.
With the Stainless Works, I was able to order direct from them, stipulate no air injection fittings from the start. They fit great, no issues since the install, no leaks.
Forgot to add, no issues hooking up to the Corsa either.
Last edited by ChumpVette; 08-06-2020 at 04:08 PM.
AFR 210's with a LE Port Job, LE Cam, and 8PSI to start.
The biggest diameter ones. Like I said, scavenging effects are minimal compared to the boost, so primary length and diameter aren't that important. Having said that, I think any header mentioned above will handle 500 hp worth of exhaust with ease, so I'd focus more on getting the highest quality you can afford, rather than worrying about header specs. Shorties might actually be a better choice for a boosted car, both for packaging reasons and for reducing underhood heat, although I'm not familiar with the C4 options currently available.
I used to have a 96 impala with the LT1, ran Borla shorties with a 150 nitrous shot. 11 second car. But sold that a while back.
Yes, I had a set of JBAs that were coated on a previous car, and you could tell a difference in the amount of heat that would radiate off them.
despite the coating on my arh headers... there is an unbelievable amount of heat radiated from them
the trans tunnel area of my car is very warm- just like with the JET hot coated TPIS headers i had.
the TPIS headers I had did not have so thick, heavy a flange area and i never had any distort/warpage issues
the ARH headers are good, but in many ways the TPIS headers (though steel) were better (fitment, installation, lighter weight, easier spark plug access)...
though someone pointed out they dont think the TPIS long tubes were equal length
Careful with that assumption. The larger diameter on some cause other compromises to be made and actually hurt overall flow. It was interesting to see the C8 test, bigger was not better.
You made the comment that boost is more important than scavaging. I have to ask why?. This is why I "want to talk headers". Obviously more boost will make more power than just better flowing exhaust. I just don't see why a blower motor wouldn't reap the same benefits as a N/A motor with headers. 500hp of air/fuel is 500hp of air and fuel. Given the push on the intake side, reduced overlap in the cam, seems scavaging would be just as important, if not more, on a blower motor. I have done some looking around and I haven't found any information relating headers directly to supercharging. I guess the question would be this: Let's say an NA engine makes 345hp. Toss 8PSI at it and it makes 450. Now with a quality set of Long tubes, are you saying the NA motor would see a larger % benefit from the headers than it would after the blower was installed?
I do not think you have much of a choice left other than ARH at this point...
TPIS still has their headers on their site. I wonder if it isn't like AS&M with TPI runners, they wait until there are enough orders to fill and then do lot production rather than tryign to guess what demand will be. I will probably give them a call to find out because their pricing is attractive.
Careful with that assumption. The larger diameter on some cause other compromises to be made and actually hurt overall flow. It was interesting to see the C8 test, bigger was not better.
You made the comment that boost is more important than scavaging. I have to ask why?. This is why I "want to talk headers". Obviously more boost will make more power than just better flowing exhaust. I just don't see why a blower motor wouldn't reap the same benefits as a N/A motor with headers. 500hp of air/fuel is 500hp of air and fuel. Given the push on the intake side, reduced overlap in the cam, seems scavaging would be just as important, if not more, on a blower motor. I have done some looking around and I haven't found any information relating headers directly to supercharging. I guess the question would be this: Let's say an NA engine makes 345hp. Toss 8PSI at it and it makes 450. Now with a quality set of Long tubes, are you saying the NA motor would see a larger % benefit from the headers than it would after the blower was installed?
The REASON blower cams typically have reduced overlap is to prevent over-scavenging of the cylinder. If they have to alter the cam design to prevent over-scavenging, it stands to reason they don't need the added scavenging from a set of well designed headers. (Not trying to be a dick here, just establishing common ground for discussion). Really all a blower engine needs is minimal exhaust restriction. So a set of shorties would actually be better than full length headers on a blower car. Not because of flow dynamics but because the smaller surface area means less heat radiated into the engine compartment.
Looks like Stainless Works (TickFlow), ARH, and Phab () are all that is left.
I wouldn't mind waiting a few months to get a set if anyone is doing build to order as well if there are other options to explore.
Could always contact melrose and see if they would put you in touch with the company that built their headers. I really like mine and plug access is a joke. Yoh may be able to get a one off set made??
As far as the coating, mine were ceramic coated and even when glowing cherry red I can hold my hand about an inch away and feel almost no radiating heat. It is pretty cool. I have regular steel ones on the 67 and those roast your legs getting out of the car lol. Mine are coated inside and out. Match perfectly to a 1406 gasket and leave that small reversion lip on my new heads. The flanges are stupid thick too.
ARH is a lot of money if you can go elsewhere. Its not as big a deal with boost as others have said. It will be a bit more forgiving I assume.
The REASON blower cams typically have reduced overlap is to prevent over-scavenging of the cylinder. If they have to alter the cam design to prevent over-scavenging, it stands to reason they don't need the added scavenging from a set of well designed headers. (Not trying to be a dick here, just establishing common ground for discussion). Really all a blower engine needs is minimal exhaust restriction. So a set of shorties would actually be better than full length headers on a blower car. Not because of flow dynamics but because the smaller surface area means less heat radiated into the engine compartment.
Obviously I haven't had time to read the book. I will say this though, I haven't seen many high HP builds with blowers using stock manifolds or shorties.
We had some discussions on the board previously about how forced induction affects the torque/hp curve. You would think with a motor like a TPI, and the long runners dictating the power curve, boost would overcome this and extend the torque curve and power curve past N/A RPM levels, but it does not. The tuning in the intake, cam, heads, and exhaust still dictate the shape, the forced induction only elevates it. SOTP in a TPI feels different, but after seeing a few published dyno plots, it is true. Just the elevated curves don't feel like you hit the wall as hard from the drivers seat. This is an important concept to grasp because the base engine still dictates the shape and the X axis RPM range of the plot. Therefor the NA performance characteristics are very important to consider, including the tuning between the intake/cam/heads/headers.
Check this article out here They do a test with a NA 427 and a Bossted 427. Not to spoil it, but they went from 661hp to 681hp NA with the addition of headers and on the boosted engine 841 to 861. It was a really good read.
By now it should come as no surprise that long-tube headers work better than stock exhaust manifolds. The question now is why? Many enthusiasts point to flow, but they seem to confuse flow with the actual pressure waves that improve power production.
The pulse tuning offered by the headers was present regardless of the presence of positive pressure in the intake tract. The same is true of intake manifolds, as long-runner intakes still offer pulse tuning under boost.
I also read this one last night from Kenny Belle. They even touch on improved exhaust flow reducing boost pressure (Remember boost is a measure of restriction to flow) adn the ability to add more boost because the exhaust flowed better, here are a few quotes to highlight:
Knowing that the best supercharged combinations start out as powerful normally aspirated combinations,
This tuning effect of both the intake manifold and exhaust is offered despite the presence of boost. Boost from a supercharger or turbocharger does not minimize the effect of the ram effect offered by the intake, nor does it alter the scavenging effect offered by long-tube headers.
It’s interesting to note that the headers offered almost exactly the same power gains at this power level as they did with the stock blower (33 hp versus 35 hp). This illustrates once again that the gains are less about absolute flow and more about scavenging
In the end, it seems the ARH being equal length should offer the best overall performance increase of all the options out there.
Originally Posted by sstonebreaker
(Not trying to be a dick here, just establishing common ground for discussion)
Don't worry about it. I know sometimes it comes off that way on the internet because of the physical separation. I try to picture "car guys around the work bench drinking beer" as the forum discussions go on. I come here to exchange information and research topics discus to keep learning. I hadn't read these articles before I started this thread, your challenge to what I thought was true got me to do some further reading.
08-06-2020, 11:44 AM
Let's talk headers for 500+RWHP
) are all that is left. 
