| I've been keeping tabs on this particular ordeal for quite some time now and just now have I had the opportunity to be able to see for myself the raw products in my hands. Currently I'm building an engine utilizing the AMS manifolds that the customer provided to me. I also had ZiNnYc send me a set of these "Ebay" manifolds that some customers who purchased them were "AMS look alikes". Thanks to ZiNnYc I was able to accomplish the comparison tests and analysis today. First I want to say that being an exhaust manifold of a cast core material and process in manufacturing some figures are going to be relative to each other and be off with a variance between .005-.015". Because of this core shift change some measurements will flucuate between each manifold. My tools that I used were of industry standard. My Dial Cailpers were calibrated at Bell Helicopter where I work and I am aerospace certified in precision tooling and machining. My credibility in that will stand as proof enough of anyone having anything to say otherwise. So to begin...here are a few images of the "ebay" manifolds that I received from ZiNnYc today. Throughout this entire post all images that you will see if items are show side by side will show "ebay manifolds" (left) and "ams manifolds" (right). I will depict which manifold you are looking at as the images progress. EBAY MANIFOLDS 
EBAY W/ AMS MANIFOLD LAYING SIDE BY SIDE
AMS MANIFOLDS 
MY CALIBRATED DIAL INDICATOR TOOL. INDUSTRY STANDARD ISSUED 
Ebay issued hardware/gasket(s)
AMS issued hardware/gasket(s)
Here I show thread pitch between the two Ebay/AMS cylinder to manifold studs. Ebay first then AMS second. Studs are exactly the same on length and thread pitch. 
A few things I noticed when dealing with the hardware was that the AMS main cylinder head to manifold nuts are larger in diameter than those of the "ebay" variety..however the "ebay" ones are taller than the "AMS" versions. Variance in hardware is the least of my worries nor should be considered being "different" than anything else. Ebay on left and AMS on right.
One of the most important things I picked up on was that the "ebay" manifolds were supplied with lock washers..which was really nice. Due to heat and vibrations nuts tend to loosen over time and having a preloaded tension against the nut keeps the nut from coming loose under conditions. The AMS manifolds did not come with this hardware. 
Next we have showing the passenger side manifold. Remember all images shown are Ebay on left and AMS on right. 
Ebay Manifold 
AMS Manifold 
Flange thickness where the manifold comes into contact with the cylinder head did vary to some extent due to the core shift and so forth. I'm just going to show you the images here but I will also at the end of this thread post all evidence and measurements between the two manifolds. Ebay Manifold 
AMS Manifold 
Ebay Manifold 
AMS Manifold 
Here is where I see quality control completely fall off. None of the manifolds shown were deburred by any means. They have extremely sharp edges and are capable of cutting ones hands quite easily. I feel that being cast iron and the amount of properties in one item can cause some serious issues if one were to cut themselves and get some form of poisoning from the iron content and so forth. Something to think about when you go handling parts. Further more...the Ebay manifolds were much more uniform in port shape than the AMS versions. Shown is where AMS manifolds have been hand machined to what I can only guess is to smooth the inlets of the ports but that is useless. The Ebay manifolds from the images show are much better in quality by appearance and touch. I am not overly happen with a product that has this amount of imperfections when a cast product is so easy to clean up once out of the mold. Here are a few images showing the ports. AMS manifold on No. 5 Cylinder & other ports 
Ebay manifold on No. 5 Cylinder & other ports 
You can plainly see where the Ebay manifold looks to be of better quality just by the layout. The AMS manifolds show to be very uneven in ports between each other. That is where quality control comes back into the picture. If you are going to put a grinder in there to clean up the ports you should at least go through and square up the flange area to make it uniform.
Overview of remaining images...
Ebay manifolds
AMS Manifolds
I also weighed each manifold as well to get feel to check to see if material was roughly the same per size and area of each product. Turns out they are pretty close to one another in weight.
Ebay manifold 
AMS Manifold 
Here are the specs between the two sets of manifolds I tested. Turbine inlet flange gasket .018" (AMS)
Turbine inlet flange gasket .018" (Ebay) Turbine inlet flange bolt hole .353" (AMS)
Turbine inlet flange bolt hole .353" (Ebay) Cylinder Head to manifold stud thread pitch 1.25 Metric (AMS)
Cylinder Head to manifold stud thread pitch 1.25 Metric (Ebay) Cylinder Head to manifold stud length 1.595" (AMS)
Cylinder Head to manifold stud length 1.600" (Ebay) Manifold to turbo stud thread pitch 1.25 Metric (AMS)
Manifold to turbo stud thread pitch 1.25 Metric (Ebay) Cylinder Head stud to manifold Nut .715" Dia (AMS)
Cylinder Head stud to manifold Nut .625" Dia (Ebay) Lock Nut thickness .325" (AMS)
Lock Nut thickness .350" (Ebay) Manifold flange thickness (to cylinder head) .500" (Ebay)
Manifold flange thickness (to cylinder head) .481" (AMS) Turbo flange thickness .745" (Ebay)
Turvo flange thickness .730" (AMS) Exhaust port width - .905" (Ebay)
Exhaust port width - .905" (AMS) Exhaust port height - 1.455" (Ebay)
Exhaust port height - 1.455" (AMS) **NOTE** - Ebay manifold has better uniformed ports, AMS shows evidence of grinding. Not symetrical on ports. .110" gasket over hang on exhaust ports on ebay manifolds. Same on AMS manifolds. Big restriction and possible turbocharger damage due to gasket material coming into contact with turbine blades at high speed. BIG PROBLEM!!!!
Also the turbine inlet flanges hang over the port as well. These small areas of detail should not be taken lightly and need to be addressed by the buyer once they get these unless AMS wants to do a bit more quality control on their parts...but I'm afraid that is out of the question. 
And lets not forget the fitment issues some if not many have or will have with the AMS/Ebay manifolds. Here are a few images of the Z1 675 turbo kit. Compressor housing hits manifold. I'm not a big fan of this as there is no clocking of any sorts that is going to help this. I have to go in and physically grind away material which lessens the material amount. But I have to do this in order to get these parts to work together.
Exhaust manifold gasket is OEM direct and at .055" thick. Same item..make and composition.
So in closing. The entire ordeal that the Ebay manifolds and the AMS manifolds being stated by AMS are different and are NOT Ebay version manifolds is a lie. These manifolds even though varying by minute differences are exactly the same. The weights are extremely close between each other as well as measurements. The last test I will do is a flow test. This will take some time as I have upgraded from the SF600 to the SF1020 flow bench for flow testing. Im waiting for the new bench to arrive. Outside of that...I wanted to put a lock on this entire situation and prove once and for all that these manifolds are in fact the same ones being sold on Ebay and can be had for MUCH cheaper pricing. Whoever AMS is using which I think many have stated is CNRacing in China they have definitely underminded AMS and their product and because of this I think that once ppl read this thread will think twice before spending money on said party for parts. I'll be doing another similar test between the border fuel rails and AMS versions as well. I just need someone to send me their new AMS rails to do comparisons.
My judgement on this situation is unbiased and I have no favorites on manifolds.....as for AMS, they get these manifolds made for $45 a set. I won't go into details about where I got the information but I assure you its quite credible an truthful. Take it for what it is. I wanted to post data and information to stop all the tt.net/3zc bitching and come on here to show once and for all that these manifolds are the same and that you certainly could have purchased the same brand on ebay for a fraction of the cost. In the attempts that AMS has made to try and somehow hide this I assure you now the blunth truth is shown and stated. There is nothing more to examine outside the flow tests I plan to do. I just now need a set of MSPs to compare to these and I'll have a confirmation on a copy with AMS in regards to MSPs manifolds. Good day
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AMS vs. Ebay Manifold Debate....Case Closed - 
