# Alternator recomendation on 84 Chevy



## BurnoutNova (Feb 22, 2013)

My 100 amp alternator seems to be on it's way out. I'm thinking about a 140 amp 1 wire alternator, but a little concerned that a 1 wire, even with low speed cut in voltage regulator might not keep up to keep my single battery e47 pump setup powered. 

Last night it was a problem, and the truck was down for a few hours while we jerry rigged another alternator on. 

Anyone have a good recommendation? Maybe part of my problem is only 1 battery, but my local plow shop recommended I go with this setup.


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## wva (Apr 26, 2010)

BurnoutNova;1605376 said:


> My 100 amp alternator seems to be on it's way out. I'm thinking about a 140 amp 1 wire alternator, but a little concerned that a 1 wire, even with low speed cut in voltage regulator might not keep up to keep my single battery e47 pump setup powered.
> 
> Last night it was a problem, and the truck was down for a few hours while we jerry rigged another alternator on.
> 
> Anyone have a good recommendation? Maybe part of my problem is only 1 battery, but my local plow shop recommended I go with this setup.


Hey there I run older trucks,and have found that I'm much better off with two batt's I use two 1000cca batt's just connect pos.to pos. and neg. to block I have had no problem with my E60 with that setup For the 2nd batt,I welded a piece of 2'' angle from inner fender to rad. support an put a batt box in it was tight fit for box add 2self drilling screws and your good. I hope this help


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## jasonv (Nov 2, 2012)

The number of wires is, by itself, not important. The total amount of copper determines the current that it is able to transfer. You can have one BIG wire, or multiple smaller ones, the results are the same.

Now here's the deal with plow pumps, batteries, wires, and alternators;

The plow pump motor will be running off some combination of the BATTERY and the ALTERNATOR. Typically, the alternator output is NOT enough to power both the vehicle AND the plow pump motor, and that fact isn't going to change with a bigger alternator. It will, however, handle a greater PORTION of the plow pump motor's demands.

Basically, the only important thing for the alternator, is that it is able to provide a power output that exceeds the total AVERAGE vehicle power demands. Since you aren't operating your plow pump motor continually, you don't need to be able to power it continually.

BUT YOU DO need to be able to provide for its instantaneous power demands!!! This is where the battery comes in. In a time when you are using your plow *frequently*, for example, DURING a job, the battery can't be allowed to run down too far. It needs to have adequate capacity to feed the plow motor AND the vehicle during this period of high demand. If you run the battery down all the way, you'll kill the vehicle's ignition when you activate the plow.

If your battery isn't up to the task, you can go with a bigger battery, or multiple batteries wired in PARALLEL.

The wire running from the alternator to the battery needs to be able to transfer the entire output of the alternator without significant voltage drop and without heating up too much. The second part of this to consider, however, is the NEGATIVE side of the circuit. Often overlooked, the negative is transferred through the alternator's body, through the ENGINE, through whatever means the engine is attached to body (often weak), and finally from the body to the battery. The wire-to-body connections often go bad, get worse, etc. If there is any doubt in your mind about the connections from the alternator to the battery, it can never hurt to run two fresh HUGE wires directly from the alternator to the battery. Keep those wires as short as practical to minimize voltage loss.

Also don't forget the plow to battery connections. If these connections are weak, it can make it appear like the battery or alternator is weak.


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## wva (Apr 26, 2010)

wva;1605465 said:


> Hey there I run older trucks,and have found that I'm much better off with two batt's I use two 1000cca batt's just connect pos.to pos. and neg. to block I have had no problem with my E60 with that setup For the 2nd batt,I welded a piece of 2'' angle from inner fender to rad. support an put a batt box in it was tight fit for box add 2self drilling screws and your good. I hope this help


forgot to mention that I replaced the batt wire from alt. with at least a #8 stranded wire.


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## ceptorman (Nov 30, 2011)

jasonv;1605581 said:


> The number of wires is, by itself, not important. The total amount of copper determines the current that it is able to transfer. You can have one BIG wire, or multiple smaller ones, the results are the same.
> 
> Now here's the deal with plow pumps, batteries, wires, and alternators;
> 
> ...


That's a lot of great info jasonv, thanks.


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## Blizzard1980 (Dec 27, 2012)

x3 on dual batteries.


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## B&B (Nov 4, 2006)

ceptorman;1605812 said:


> That's a lot of great info jasonv, thanks.


This is where you have to decide what to accept as good info from the Internet as there's some misinformation as well as some misinterpreted info in that post.

One is obviously he doesn't know what a one wire alternator is...


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## jb1390 (Sep 23, 2008)

B&B;1605895 said:


> This is where you have to decide what to accept as good info from the Internet as there's some misinformation as well as some misinterpreted info in that post.
> 
> One is obviously he doesn't know what a one wire alternator is...


The middle parts are decent, i almost stopped reading after the incorrect interpretation of a one wire alternator. The beginning and end have a bit of incorrect information though.

Two batteries will never hurt, to the op, how is your ratio of driving to plowing? If your engine has a chance to spin the alternator at elevated speeds between accounts i bet you'll be just fine with a one wire.


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## GSS LLC (Jul 7, 2012)

I run dual batteries and the 100 amp alt on my four 80's Chevy trucks. Works fine.


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## 2COR517 (Oct 23, 2008)

jasonv;1605581 said:


> The number of wires is, by itself, not important. The total amount of copper determines the current that it is able to transfer. You can have one BIG wire, or multiple smaller ones, the results are the same.


Incorrect. The majority of the electron travel is on the surface of the wire strand. That is why conductors for heavy current applications are always stranded, much more surface area on 100 small strands than 1 large strand.

Jason's knowledge of vehicle electrical systems varies from slightly misguided to grossly innacurate. Proceed with caution.


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## jb1390 (Sep 23, 2008)

2COR517;1605945 said:


> Incorrect. The majority of the electron travel is on the surface of the wire strand. That is why conductors for heavy current applications are always stranded, much more surface area on 100 small strands than 1 large strand.
> 
> Jason's knowledge of vehicle electrical systems varies from slightly misguided to grossly innacurate. Proceed with caution.


2nd part about proceeding with caution is correct on much of his advice.

First part, while you are technically partly correct, cross sectional area has more to do with current carrying capability than number of strands, on a low voltage dc system. When you start talking about high frequency signal transmission, then things like characteristic impedance start to matter. But for 12 volt or even 120 volt systems, solid or stranded won't make a detectable difference.


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## jb1390 (Sep 23, 2008)

Sorry, double post.


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## Rat_Power_78 (Sep 16, 2008)

Everyone has thier own opinions when seeking advice on the internet, so be cautious of who you listen to. That being said, the following is what I experienced with a similar truck:

When I was running my '76 K20 as my main plow truck, I was always plagued with a lack of electrical power and spent far too much time trying different things to solve the issue. One thing to consider: If the alternator you are looking at is rated at 140 Amps, how many RPM is that rating at? Often, it seems high-amp alternators dont put out near what you would think at the low RPMs seen while maneuvering at low speeds. According to a local alternator/starter shop, it is possible to build an alternator that will put out more amps at low RPM than your typical generic "140 amp alternator." If you have a known, trusted shop like this in your area, seek out their advice. I did not find this out until I retired the truck from regular service, so I had a slightly different solution that worked well for me.

Stock, the truck ran a 10si alternator (charging wire plus the 2-prong factory plug), which put out 63 amps stock. That was the biggest available to me in that case size I changed to a 12si alternator (same wiring setup), rated at 93 amps. the case of it is slightly larger, but I was able to fit it in my application. I dont recall if I had to change a bracket or not. The real beauty of this alternator is every parts house stocks them, making replacements easy and quick to get, and the price was reasonabe-far more so than the aftermarket high-amp units. I had been running dual batteries for many years prior to this, but I wanted to make sure they were getting a good charge. We retained the stock charging wire and added an 8 guage wire from the charging post on the alternator directly to each battery. We also ran an 8 guage wire to the plow solenoid where the positive battery cable connects to it. This setup cured my power issues and I ran it for several years before replacing the truck.

A note on dual batteries- there was a factory auxilary battery tray made if you dont want to fab your own, not sure if you can still get them from GM or if you would need to find a used one. Be sure to run a ground from battery #2 to the frame instead of to battery #1 as it seems to work better. Finally, and most importantly, be sure to use two new, identical batteries. I learned the expensive way that one new and one used will kill each other very quickly. Same goes for using two different batteries. You may be able to use an isolator to get around this, but I personally would not.


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## jb1390 (Sep 23, 2008)

Rat_Power_78;1606289 said:


> Everyone has thier own opinions when seeking advice on the internet, so be cautious of who you listen to. That being said, the following is what I experienced with a similar truck:
> 
> When I was running my '76 K20 as my main plow truck, I was always plagued with a lack of electrical power and spent far too much time trying different things to solve the issue. One thing to consider: If the alternator you are looking at is rated at 140 Amps, how many RPM is that rating at? Often, it seems high-amp alternators dont put out near what you would think at the low RPMs seen while maneuvering at low speeds. According to a local alternator/starter shop, it is possible to build an alternator that will put out more amps at low RPM than your typical generic "140 amp alternator." If you have a known, trusted shop like this in your area, seek out their advice. I did not find this out until I retired the truck from regular service, so I had a slightly different solution that worked well for me.
> 
> ...


Very nice writeup ratpower, wish there was a way to "like" this post


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## Rat_Power_78 (Sep 16, 2008)

Thanks. Hopefully it can help someone. Years and years of frustration all condensed to a couple paragraphs...


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## B&B (Nov 4, 2006)

Rat_Power_78;1606289 said:


> Be sure to run a ground from battery #2 to the frame instead of to battery #1 as it seems to work better.


You were doing very well up until you stated this. Never run a primary ground to the frame, always go to the engine or you set yourself up for unnecessary potential problems.


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## ceptorman (Nov 30, 2011)

B&B;1605895 said:


> This is where you have to decide what to accept as good info from the Internet as there's some misinformation as well as some misinterpreted info in that post.
> 
> One is obviously he doesn't know what a one wire alternator is...


Thanks B&B, after reading your twin battery install I now know what you mean. Does this fall under the old saying..."if you can't dazzle them with brilliance, baffle them with bullish*t"?


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## Rat_Power_78 (Sep 16, 2008)

B&B;1606819 said:


> You were doing very well up until you stated this. Never run a primary ground to the frame, always go to the engine or you set yourself up for unnecessary potential problems.


What sort of problems? It seemed to work fine this way, but if its wrong, I would like to know for next time.


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## B&B (Nov 4, 2006)

Rat_Power_78;1607328 said:


> What sort of problems? It seemed to work fine this way, but if its wrong, I would like to know for next time.


Think about these couple things.

1) Why doesn't the OEM run the battery (either main or aux) ground cable to the frame?

2) What are all your heavy current components grounded through? I.e. starter, alternator etc?

3) On a aux battery install with the battery grounded to the frame, what is completing the ground path on it's way back to those same heavy current components and ultimately, the main battery?

Remember, ground is one half of the current loop between the supply (battery) and the loads in the electrical system.


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## Rat_Power_78 (Sep 16, 2008)

B&B;1607634 said:


> Think about these couple things.
> 
> 1) Why doesn't the OEM run the battery (either main or aux) ground cable to the frame?
> 
> ...


I dont know how I missed this originally. I went back and looked at the truck today, and what I had done when hooking it up goes like this: the ground on my auxilary battery is a 2-guage cable that runs down and bolts to a clean spot on the frame. The part I forgot is there is a second cable that runs from this same spot on the frame up to the block. I think the idea behind this was to ground everything to everything. I was taught that ground issues are the most common cause of automotive electrical problems, and we wanted to eliminate this as a possible issue on that truck. Considering the age of the truck, adding a known good ground from engine to frame seemed to be a good plan. I didnt think it would cause a problem connecting it this way, as it seems to be accomplishing the same task, but then again I could be wrong. Would you typically connect to the block or to the main battery ground post on an install like this?

I have a lot of respect for you and the amount of knowledge you have on such subjects. Besides, not just anybody can get a smilie named after them.


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## B&B (Nov 4, 2006)

Rat_Power_78;1607816 said:


> I dont know how I missed this originally. I went back and looked at the truck today, and what I had done when hooking it up goes like this: the ground on my auxilary battery is a 2-guage cable that runs down and bolts to a clean spot on the frame. The part I forgot is there is a second cable that runs from this same spot on the frame up to the block. I think the idea behind this was to ground everything to everything. I was taught that ground issues are the most common cause of automotive electrical problems, and we wanted to eliminate this as a possible issue on that truck. Considering the age of the truck, adding a known good ground from engine to frame seemed to be a good plan. I didnt think it would cause a problem connecting it this way, as it seems to be accomplishing the same task, but then again I could be wrong. Would you typically connect to the block or to the main battery ground post on an install like this?
> 
> I have a lot of respect for you and the amount of knowledge you have on such subjects. Besides, not just anybody can get a smilie named after them.


I suspected you omitted the part where you also had a second cable from the frame to the engine thus completing the path from the battery to the engine with a short stop over on the frame. I say this because if you didn't add the second cable when you added the battery you would have seen little benefits from it and you would have already fried the stock small gauge battery to frame ground those truck have. Because you would have been depending on it to "finish" the path from the aux battery to primary battery. And this is where having it wired the way you do still isn't good. Because with the aux battery going to the frame first you're depending on that added frame-to-engine cable to always do it's job, which is what I meant by setting yourself up for issues later. Because if that cable becomes loose or corroded on either end over time guess what? Now you're unknowingly back to depending on the stock small gauge frame-to-battery ground which will go up in smoke in short order. And it will be when you're depending/demanding on the aux battery the most, usually at 3am in a blizzard. On an older truck (such as these) it wouldn't put you dead in the water since all you'll lose is the available capacity of the aux battery, and the tail lamps (because they receive their ground via the frame). But, on a late model with plenty of electronics you just unknowingly and unnecessarily created a very costly scenario where not only anything that receives it's ground through the frame (electric shift 4x4, ABS module, fuel pumps etc) will cease working, the high current draw will also search for a ground path back to the other battery by another means. And that may be through some very sensitive electrical components and even some mechanical components. I've seen brake lines, e-brake and shifter cables burned open from poor grounds. And steel braided fuel lines glow red hot when the plow is operated. And even internal transmission and transfer case components micro-welded because something was trying to ground through it from an improper ground routing or poor connection. It must be realized that if you don't provide the proper ground it will find it's way back to the battery through anything else it can. And some of those things it may find are very expensive to replace.

So, in a nutshell, while you do understand the importance of grounding (good for you) you also must understand in what order to ground them so you don't set yourself up for a future issue. In your case with your aux battery grounds, change them around. Ground the aux battery to the engine FIRST as it's the priority "home base" for the grounding path back to the main battery and all it's loads. And THEN run your short ground cable from the engine to the frame. This way if you lose the engine to frame ground at some point nothing major will happen as the aux battery is still grounded directly to the engine. And if you ever lost the engine to frame ground nothing will happen except you'll lose the tail lamps and nothing with a high current draw can "search" for the missing ground through something else. Because you never created any self inflicted grounding issues in the first place.


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## jasonv (Nov 2, 2012)

B&B;1605895 said:


> This is where you have to decide what to accept as good info from the Internet as there's some misinformation as well as some misinterpreted info in that post.
> 
> One is obviously he doesn't know what a one wire alternator is...


To translate: Ignore everything from "B&B" as he's clearly trying to spread confusion. Probably a dealer or some other crap trying to make a buck.


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## jasonv (Nov 2, 2012)

2COR517;1605945 said:


> Incorrect. The majority of the electron travel is on the surface of the wire strand. That is why conductors for heavy current applications are always stranded, much more surface area on 100 small strands than 1 large strand.
> 
> Jason's knowledge of vehicle electrical systems varies from slightly misguided to grossly innacurate. Proceed with caution.


Larger wire has more strands.

Think first, respond later.


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## Rat_Power_78 (Sep 16, 2008)

B&B;1607974 said:


> I suspected you omitted the part where you also had a second cable from the frame to the engine thus completing the path from the battery to the engine with a short stop over on the frame. I say this because if you didn't add the second cable when you added the battery you would have seen little benefits from it and you would have already fried the stock small gauge battery to frame ground those truck have. Because you would have been depending on it to "finish" the path from the aux battery to primary battery. And this is where having it wired the way you do still isn't good. Because with the aux battery going to the frame first you're depending on that added frame-to-engine cable to always do it's job, which is what I meant by setting yourself up for issues later. Because if that cable becomes loose or corroded on either end over time guess what? Now you're unknowingly back to depending on the stock small gauge frame-to-battery ground which will go up in smoke in short order. And it will be when you're depending/demanding on the aux battery the most, usually at 3am in a blizzard. On an older truck (such as these) it wouldn't put you dead in the water since all you'll lose is the available capacity of the aux battery, and the tail lamps (because they receive their ground via the frame). But, on a late model with plenty of electronics you just unknowingly and unnecessarily created a very costly scenario where not only anything that receives it's ground through the frame (electric shift 4x4, ABS module, fuel pumps etc) will cease working, the high current draw will also search for a ground path back to the other battery by another means. And that may be through some very sensitive electrical components and even some mechanical components. I've seen brake lines, e-brake and shifter cables burned open from poor grounds. And steel braided fuel lines glow red hot when the plow is operated. And even internal transmission and transfer case components micro-welded because something was trying to ground through it from an improper ground routing or poor connection. It must be realized that if you don't provide the proper ground it will find it's way back to the battery through anything else it can. And some of those things it may find are very expensive to replace.
> 
> So, in a nutshell, while you do understand the importance of grounding (good for you) you also must understand in what order to ground them so you don't set yourself up for a future issue. In your case with your aux battery grounds, change them around. Ground the aux battery to the engine FIRST as it's the priority "home base" for the grounding path back to the main battery and all it's loads. And THEN run your short ground cable from the engine to the frame. This way if you lose the engine to frame ground at some point nothing major will happen as the aux battery is still grounded directly to the engine. And if you ever lost the engine to frame ground nothing will happen except you'll lose the tail lamps and nothing with a high current draw can "search" for the missing ground through something else. Because you never created any self inflicted grounding issues in the first place.


Ok got it now. Mine will get the grounds fixed on it before the next time I spin the key. I do understand the importance of grounding, but like you said, I didnt know the order in which things were grounded mattered. Thanks, B&B, I feel a little smarter now. Thumbs Up


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## tuney443 (Jun 25, 2006)

jasonv;1608033 said:


> To translate: Ignore everything from "B&B" as he's clearly trying to spread confusion. Probably a dealer or some other crap trying to make a buck.


Until you have an icon placed in your honor---STFU!!! 99.999% of what B&B has forgot you will NEVER learn.


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## BurnoutNova (Feb 22, 2013)

Thanks for all of the good information. I do understand most of what you guys are recommending I make sure is in good shape as far as having a good battery, good grounds etc. 

I guess my main question was is there a specific, off the shelf alternator that has the ability to produce more current at low rpms than a typical 1 wire, or even a stock style 2 wire alternator. I'm familiar with how a 1 wire works, with the voltage regulator not allowing the alternator to develop current unless the rpm's are up over 1800-2500 rpm in some cases. I think that the answer is a shop needs to modify it for my, and I do have a shop like that in my area, so I will contact them about a custom alternator.


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## jb1390 (Sep 23, 2008)

jasonv;1608033 said:


> To translate: Ignore everything from "B&B" as he's clearly trying to spread confusion. Probably a dealer or some other crap trying to make a buck.


This is plowsite heresy, and should be grounds for removal from the site.



jasonv;1608037 said:


> Larger wire has more strands.
> 
> Think first, respond later.


See if your mom will let you ride your bigwheel down to the local chepot depot. Ask the nice man in the isle if he will let you climb on a ladder so you can see the second shelf. Take a look at the various types of wire, especially the 14 gauge stranded and the 12 gauge solid. You will (likely not) quickly realize as most people would that the gauge is how cross sectional area of wire is measured. It has nothing to do with number of strands, as the 12 gauge wire is significantly larger than the 14 gauge stranded. FWIW, a change of 3 AWG is double the cross sectional area....you can get a 6 AWG wire by using 4 x 12 AWG wires, solid or stranded won't matter.

Think first, please don't respond later.


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## jb1390 (Sep 23, 2008)

BurnoutNova;1608135 said:


> Thanks for all of the good information. I do understand most of what you guys are recommending I make sure is in good shape as far as having a good battery, good grounds etc.
> 
> I guess my main question was is there a specific, off the shelf alternator that has the ability to produce more current at low rpms than a typical 1 wire, or even a stock style 2 wire alternator. I'm familiar with how a 1 wire works, with the voltage regulator not allowing the alternator to develop current unless the rpm's are up over 1800-2500 rpm in some cases. I think that the answer is a shop needs to modify it for my, and I do have a shop like that in my area, so I will contact them about a custom alternator.


There was a larger body alternator that Chevy used in the late 90's police vehicles. It does put out a lot of current at low RPM's. I installed this alternator in my old truck, I am not sure if it would fit with your brackets, but it might be worth a shot. I took some pics of the install on mine and started a thread, the link to it is below. You could see if you make it work in your application, you might need pulley changes, etc, and you could splice your current wiring to adapt the the plug that the alternator would accept.

If you want to go this direction, I'd be happy to provide any other information that I can if it is not in the thread.

Take a look at the pic of the voltmeter with a nearly 1000 watt load at idle 

http://www.plowsite.com/showthread.php?t=119262


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## jomama45 (Dec 25, 2008)

jasonv;1608033 said:


> To translate: Ignore everything from "B&B" as he's clearly trying to spread confusion. Probably a dealer or some other crap trying to make a buck.





jasonv;1608037 said:


> Larger wire has more strands.
> 
> Think first, respond later.


LMAO, I guess he told you two................................... :laughing:


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## B&B (Nov 4, 2006)

jomama45;1608518 said:


> LMAO, I guess he told you two................................... :laughing:


Too funny Joe. :laughing:


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## 2COR517 (Oct 23, 2008)

jomama45;1608518 said:


> LMAO, I guess he told you two................................... :laughing:


I to think think the scolding for the two of us is too funny.....


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