What do you mean “higher hp remans”?
https://holdersdiesel.com/collection...erstroke-parts

I don’t believe in 40hp and 70hp injectors, you have options to go with higher flowing nozzles and bodies with more volume. Injectors alone don’t add horsepowe, you will have to have custom tuning written to take advantage of the upgraded injectors.
You send your injectors in and they have remans made already and they’ll send a flow sheet for those injectors.

I had them in my hands in just 3-4 days.

If I remember correctly I mailed my injectors to Holder’s and they mailed me a set of injectors that were already made. I got a slight discount because I had a full set of brand new 30% nozzles on my core injectors from attempting a rebuild. My injector bodies were out of spec so the new spool valves, rebuild kits abd solenoids were a waste of time and money. Anyway, I took a hit and just sent them my old injectors and new nozzles and they mailed my fresh premium rebuilds. I had them in less than a week I believe.
Here is a post from a very knowledgeable guy on another forum:
First off, I want to make it clear that I am by no means an expert in regards to 6.0 Powerstroke injectors but this thread is designed to bring conversation, provide information and to seek out information from those with a broader knowledge base of how the injectors work. All statements made in this thread by me are purely theoretical and I have no real life testing/data to conclusively say anything I saw is definitive or written in stone. This all stemmed from the issues I have been having with my truck and wanting to get to know the intricacies of what I was dealing with. Boy I was not ready for all of that.

Lets start!

6.0 injectors are an HEUI injector. HEUI stands for Hydraulic Electric Unit Injector. They work by utilizing high pressure oil provided by a high pressure oil pump (HPOP) and pressurize the fuel inside the injector. High pressure oil enters the injector body applying pressure to an intensifier piston. That piston pressurizes fuel at a rate of 7 time the oil pressure (approximately 26,000 psi for our trucks). The solenoids on the injectors are controlled via the FICM.

So what so all this mean?

Let’s talk about the FICM. Fuel Injection Control Module. A common link to injector failure can be linked to the FICM. Another can be linked to fuel pressure but we’ll discuss that later.

An OEM International FICM is designed to operate at 48 volts. Therefore the solenoids on the injectors are designed for 48 volts as well. FICM’s can be modified to accommodate higher voltages (ie; 53v and 58v), they can be specifically tuned by several companies, or the can be left alone and in a stock configuration.

What are the affects of running higher voltage FICM’s? Many people will say that low voltage will cause failure of our injectors. I’m curious as to how. I’m not an engineer by any means, I’m not a professional electrician but my understanding of electricity is that low voltage is far less likely to cause damage than an over voltage would. I mean consider this: take a welder designed to operate on 110v. What happens if you plug that welder into an outlet wired for 220v (assuming the plug fit)? Chances are you’d fry that welder since it isn’t designed for that higher voltage. What happens if that same 110v welder was plugged into an outlet designed for less than 110v, say 75v (just an example btw)? It won’t operate because it won’t have the power requirement necessary to facilitate its operation. So how does low voltage actually “destroy” injectors? Although that analysis was using numbers that aren’t accurate, it’s just an example. However, taking an injector designed to run on 48v and running it on 58v could be harmful. Could be. Now, don’t take that as me saying higher voltage FICM’s will destroy injectors. As of right now, I’m unaware of any factual data to support this logic, which is purely theoretical. There have been numerous reports that many people have seen quieter operation from their injectors using the 58v FICM and even better atomization because the spools are moving faster. Is faster spool valve action better? I don't know. What is the long term outcome though? It’s uncertain right now and this is just some food for thought.

Now let’s talk about fuel pressure and its affects on injector operation/life. Inside that injector body are moving parts. The fuel pressure to the injectors is necessary to keep those moving parts from just “slamming” inside the injector body thus preventing damage to those components and potentially rendering the injector useless. Basically the fuel within the injector body works similar to an air-to-liquid accumulator, like a buffer/shock absorber. It’s provides a dampening affect protecting those components. Currently the fuel system when operating with the Ford upgraded Blue Spring, the fuel pressures are generally between 65-70psi and at WOT down to about 60psi (I haven’t actually measured that, I’m just basing that off other users data). It’s necessary to have adequate fuel pressure to sustain operation of the injectors and to ensure they function properly.

Since we’re on the topic of fuel pressure to the injectors, lets talk about banjo bolts. The 6.0 banjo bolts on the cylinder heads have a check valve in each bolt. The check valve is designed to prevent pressure surges in the fuel rails and to keep fuel in those rails. As to the pressure surges, think of it like a waterbed; if you sit down on the waterbed, it will create a wave like affect within the water bladder. Imagine the fuel rail in the head as that water bladder. At some point, the rhythmic nature of the fuel would cause air in the rails which could be detrimental to the operation of the injector. The check valve is designed to prevent that in order to prevent the injector from losing is fuel pressure and/or cavitating (that’s my way of explaining it). Many people claim that the check valve in the bolt “starves” the fuel injectors at the back of the cylinder head. Interesting concept. I’m curious what data is out there to support this claim. The fact of the matter is this; the 6.0 (deadhead) fuel system is completely different from the 6.4 (common rail fuel system). The banjo bolts on the 6.4 are actually designed to come off the back of the cylinder head…..because they serve a different function. Many will say the 6.4 bolts are better for the 6.0 because “why would the engineers change it up if it they weren’t bad?” Well it’s simple. They changed it up because the design of the system is entirely different. So, with all that being said, 6.0 banjo bolts are not bad for 6.0’s. 6.4 banjo bolts are not bad for 6.0’s either. Understanding how the system works gives you the ability to make an informed decision on what components to/not to install on your vehicle. I currently do not run 6.4 banjo bolts.

How about injector sizes?? Many people will see things such as 155/30, 190/100, 205/150 but not really know what that means. Well to understand that, you have to understand the injector and how it moves fuel. A stock injector moves fuel in pulses. Basically a stock injector will empty 135cc’s a fuel in 1,000 pulses. I don’t know the rate in which it empties the injector but for this purpose, will call that rate “X”. So a stock injector empties 135 cc’s fuel at a rate of X. An injector labeled as 155/30 means that in 1,000 pulses, that injector moves 155 cc’s of fuel and it will empty that injector of fuel 30% faster than stock (X). 190/100= 190cc’s of fuel in 1,000 pulses 100% faster than stock (X). There are also injectors that are 155/stock, 175/stock and so forth. That means the injector moves 155/175cc’s of fuel but it empties at the same rate as a stock injector (X). The size injector you opt to run in your vehicle will depend primarily on what your intended purpose for the truck is. Just remember, if you move lots of fuel, you’ll need more air to clean that fuel up in the form of a bigger turbo. Consult your injector/turbo supplier for the setup that is best suited for your application.

I really hope the information provide can be useful to anyone who chooses to read it. If I have distorted any information, or have any of it completely skewered please let me know, not just for other's benefit but for my own. I’ll update this as necessary.

If you are looking for just a little more power over stock I’d venture to say 155/30 premiums would be what you would want. Someone else may chime in but these are my thoughts.

If you are looking for more power, stock injectors are just fine. But you need programming to tell the injectors to inject more fuel. Check out ficmrepair for their FICM tune upgrades. Those seem to be the most economical way to get 40 or 80 more horsepower.